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THE 

ENGINEER'S  ENCYCLOPAEDIA 

COJfTAINING  A   HISTORY    OF  THE  DISCOVERT  AND    APFLICATION  OF 

STEAM,    WITH  ITS  PRACTICE  AND    ACHIEVEMENTS  FROM 

THE  EARLIEST  PERIOD  TO  THE  PRSEENT  TIME. 

THE   WHOLE   FORMING   A   PRACTICAL   GUIDE  TO 

THE  MOST  RECENT  APPROVED    METHODS  OF  CONSTRUCTION,  WITH 
EXAMPLES  DRAWN  TO  SCALE  IN  SIMPLE  WORKSHOP  FORM. 

WITH   RULES   AND   FORMULAE   RELATING  TO 

BOILERS,  STATIONARY  ENGINES,  MARINE  ENGINES,  LOCOMOTIVES,  AND  THE 
TREATMENT  AND   REGULATION   OF  STEAM. 

A  NEW  EDITION  CONTAINING  A  COPIOUS  APPENDIX 

DESCRIPTIVE  OF  MACHINE  TOOLS,  HAMMERS,  ELECTRIC   ENGINEERING  DYNA- 
MOS, MAGNETS,  MOTORS  AND  OTHER  APPLIANCES  OF  ELECTRICITY,  ETC. 


BY 

JOHN   F.  WINTON,  Engineer,  and  W.  J.   MII.LAR,  Civil  Engineer, 

Author  of  '■^Modern  Workshop  Practice."  Author  of  ^'■Principles  of  Mechanics,"  etc. 


The  "Old  Ironsides,"  1832. 

ILLUSTRATED  BY  OVER  SIX   HUNDRED  ENGRAVINGS  IN  THE  TEXT  AND 
A  SERIES  OF  SEPARATE  PLATES. 


PHILADELPHIA: 

GEBBIE    &    CO.,    PUBLISHERS, 

1893. 


copyrighted,  1888,  by  Gebbie  &  Ca 


PREFACE. 


THE  object  of  this  publication  is  to  supply  the  practical  Engineer  and 
Mechanic  with  a  trustworthy  guide  to  the  varied  operations  of  the 
Workshop  in  a  convenient  form  and  at  a  moderate  price.  It  is  written 
by  practical  men,  well  acquainted  with  the  operations  which  they  describe, 
and  seeks  to  convey  to  the  workman  detailed  directions  regarding  his 
work  in  language  such  as  he  is  familiar  with,  and  at  the  same  time  to 
state  clearly  the  higher  principles  upon  which  these  operations  are  based, 
and  on  which  they  depend  for  success. 

The  importance  of  this  book  for  those  engaged  in  all  branches  of  Engi- 
neering, etc.,  will  at  once  be  seen  by  an  examination  of  the  Summary 
of  Contents.  From  this  summary  may  also  be  gathered  a  general 
idea  of  the  scope  of  the  work,  and  of  the  manner  in  which  the  various 
subjects  are  treated.  After  a  brief  notice  of  Coal  and  Coal-mining, 
the  author  discusses  the  forms  of  Boilers,  their  construction,  the  use  of 
Steel  and  the  treatment  of  Steam  ;  the  Land  or  Stationary  Engine  in  its 
many  forms  and  uses  ;  the  Marine  Engine  of  the  present  day  as  well  as 
that  of  fifty  years  ago,  and  the  important  subject  of  the  Screw  Propeller ; 
the  Locomotive  Engine  and  Tender,  British  and  American,  including 
details  of  recent  improvements  and  special  forms  rnade  for  different  rail- 
ways. Numerous  Tables,  Rules  and  Formulae  are  given  throughout  the 
book,  rendering  it  a  useful  companion  in  the  counting-houses  and  design- 
ing rooms  of  locomotive  works  and  machine  shops. 

Besides  the  useful  working  drawings,  of  which  there  are  nearly  700 
in  all,  there  are  sixteen  large  folding  plates  of  important  examples  and 
twenty-five  tables  for  reference  and  instruction  in  every  possible  re- 
quirement for  calculation.  These  illustrations  teach  through  the  eye  in  a 
clear  and  perspicuous  manner.  They  are  executed  without  shade  lines  in 
order  that  they  may  all  the  better  meet  the  requirements  of  practical  men. 

This  book  will  be  found  a  most  useful  assistant  not  only  to  those 
charged  with  the  duty  of  carrying  on  and  superintending  work,  but  also 
to  intelligent  workmen  who  seek  to  understand  the  best  modes  of  per- 
forming the  operations  in  which  they  are  engaged,  as  well  as  to  all  learn- 
ers, whose  aim  should  be  to  acquire  thoroughly  principles  as  well  as  hand 


PREFACE. 

skill,  and  so  qualify  themselves  for  the  higher  positions  of  their  trades. 
It  will  also  be  found  of  great  service  as  a  means  of  preparing  those  who 
desire  to  pass  the  special  examination  recently  proposed  by  the  Trades 
Union  Congress  in  England  and  Scotland  to  be  instituted  for  men  having 
charge  of  steam  engines  or  boilers.  As  an  example  of  the  importance  of 
this  subject  to  all  who  are  in  any  way  interested  in  or  have  the  care  of 
Boilers,  it  was  stated  in  the  House  of  Commons,  on  the  second  reading 
of  the  Boilers  Explosio7t  Bill  (22d  Feb.,  1882),  that  through  Boiler 
Explosions  one  man  was  killed  on  an  average  every  four  days,  and  two 
thousand  persons  maimed  from  the  same  cause  during  the  past  few  years. 

In  order  that  the  reader  may  thoroughly  understand  all  the  subject,  the 
practical  part  of  the  work  is  prefaced  by  a  thorough  and  concise  history 
of  the  discovery  and  progress  of  perfecting  the  application  of  steam  to  its 
present  power  and  perfection. 

The  story  of  the  glimpse  that  the  ancients  had  of  its  possibilities,  130 
B.  c,  in  the  ^olipile  of  Hero,  and  next  the  somewhat  uncertain  statement 
that  Blaxo  de  Garay  showed  a  steamboat  in  the  harbor  of  Barcelona  in 
1543;  then  Solomon  de  Caus  in  1615,  Giovanni  Branca  in  1629,  the 
Marquis  of  Worcester  in  1663,  Papin,  the  real  discoverer  of  the  first  prac- 
tical step,  in  1689,  Savary  in  1699,  and  Newcomen  in  1705,  who  improved 
on  Papin  and  Savary,  and  by  using  both  air  and  steam  first  applied  the 
power  to  pumping  water  out  of  mines,  until  Watt,  in  1765,  on  getting 
one  of  Newcomen's  models  to  repair,  made  the  discovery  of  improvements 
which  have  revolutionized  the  industries  and  commerce  of  the  world. 

The  story  of  its  practical  adoption  in  steamship  propulsion  and  in  rail- 
road locomotion  will  be  found  circumstantially  related,  and  the  share  of 
each;  the  two  Stephensons,  Trevethick,  Symington,  Murdoch,  Ericsson 
and  others  of  England,  and  Oliver  Evans,  Fulton,  John  Fitch,  Stevens, 
Long,  Baird,  Norris,  Harrison,  Eastwick,  Baldwin,  etc.,  of  America,  all 
receive  due  notice  and  their  record  of  improvements. 

This  plan  of  minutely  tracing  and  describing  each  successive  improve- 
ment must  prove  both  interesting  and  instructive,  because  the  student 
interested  in  these  details,  when  fully  informed  as  to  how  the  present  per- 
fection has  been  won  step  by  step,  will  be  better  able  to  understand  the 
present  condition  of  Modern  Mechanics,  and  in  his  turn  may  conclude 
that  improvements  are  yet  possible. 


CONTENTS  OF  THE  HISTORY  OF  STEAM. 

James  Watt  :  page 

Birth  and  Ancestry  . v 

Childhood  and  Education '        .         .         .         .  vii 

Settles  in  Glasgow  as  a  Mathematical  Instrument  Maker  .         .         .  ix 

Marries  his  Cousin,  Miss  Miller xi 

Gets  a  Small  Model  of  Newcomen's  Steam  Engine  to  Repair  .         .  xi 

The  Discovery  of  the  Application  of  Steam  to  Mechanics  .         .         .  xi 

History  of  the  Steam  Engine  Before  the  Time  of  Watt: 

Hero  refers  to  it  Three  Centuries  B.  c xii         . 

The  .^olipile,  B.  c.  130  xii 

The  yEolipile  the  same  Principle  as  the  Rotary  Engine  .         .         .  xiii 

Blaxo  de  Gary's  Steamboat  in  Barcelona,  1543 xiv 

Solomon  de  Caus'  Steam  Toy,  161 5 xv 

Giovanni  Branca's  Steam  Wheel,  1629 xvi 

The  Marquis  of  Worcester's  Engine,  1663        ....         0         .  xvii 

Savary's  Steam  Engine,  1699 •  xviii 

Papin's  Air  Engine,  with  which  he  Combined  Steam,  1689       .         .         .  xix 

Newcomen's  Steam  Engine,  1705 xxi 

Humphrey  Potter's  Skulking  Gear  .......  xxiii 

Watt's  Improvements  on  the  Steam  Engine  as  a  Drawing  and  Pump- 
ing Machine: 

Discovery  of  the  Condenser     .........  xxv 

Watt's  "  Modified  "  really  the  First  Steam  Engine xxvi 

Economizing  Fuel  ..........  xxvii 

Watt  Associates  with  Dr.  Roebuck  .......  xxvii 

Watt's  Partnership  with  Bolton         ........  xxviii 

Occupation  as  a  General  Engineer  .......  xxviii 

Surveys  the  Caledonian  Canal  ........  xxix 

Extension  of  Patent  on  Steam  Engine       .......  xxx 

Impulse  to  Mining  Enterprise  ........  xxxi 

First  Introduces  Parallel  Motion      ........  xxxii 

Double-acting  Engine      .         .         .         .         ,         .         ,         ,         .         .  xxxii 

Watt's  Governor      ...........  xxxiii 

Model  of  a  Steam  Engine,  by  Murdock,  Watt's  Assistant,  1784         .         .  xxxv 

The  Life  of  George  Stephenson: 

Birth  and  Parentage         ..........  xxxviii 

Works  in  the  Fields  at  Eight  Years xxxix 

Assistant  Fireman  at  Fifteen  Years  .         .         .         .         .         .         .  xl 

Good  Engineer  at  Eighteen,  but  did  not  know  his  Alphabet      .         .         .  xliii 

Self- Taught,  Married,  and  a  Cobbler  at  Twenty-One         ....  xliv 

Birth  of  his  son,  Robert  Stephenson,  the  Great  Engineer  ....  xlv 

Boss  Colliery  Engineer  and  Planner  of  Machinery  at  Thirty-One       .         .  xlvi 

Cugnot's  Engine,  1770     .         .         . xlviii 

Trevethick's  Engine,  1803        .........  xlviii 

Blenkinsop's  Tooth-Wheeled  Locomotive,  181 1        .         .         .         .         .  xlix 

Brunton's  Stilt  Locomotive,  1813 xlix 

Blackett's  Theory,  1812 1 

Stephenson's  Locomotive,  1815         .         .         .         .         .         .         .         ,1 

Stephenson's  Draught  for  the  Furnace  Discovered li 

Education  of  Robert  Stephenson li 

(i) 


11 


CONTENTS. 


PAGE 

George  Stephenson's  Discovery  of  the  Safety  Lamp  .         .         .         .  lii 

George  Stephenson,  Engineer  of  Stockton  &  Darlington  R.  R.  .         .  lii 

George  Stephenson's  Locomotive  Works  at  Newcastle      .         p         .         .lii 

George  Stephenson  Starts  a  Train  (1825)  at  Twelve  Miles  an  Hour  .  lii 

"               "              Examined  Before  a  Committee  of  Parliament  in  Ref- 
erence to  Railroads  .....  liii 

"  "  Competes  with  the  Rocket  Against  the  Novelty  and 

Sanspareil,  and  won  the  prize  of  ;^550,  making 

over  Twenty-nine  Miles  an  Hour  (1829)  .  Iv 

Manchester  and  Liverpool  Regularly  Connected  by  Steam  Railway,  1830  Ivi 

London  &  Northwestern  Railroad  Opened,  1831 Ivii 

George  Stephenson  the  Head  of  the  Railroad  World,  1840        .         .         .  Ivii 

Death  of  George  Stephenson,  1848 Ix 

1  H'E  History  of  Steam  in  America  : 

The  Share  and  Claims  of  Americans  and  Others  in  the  Discovery  and 

Application  of  Steam         .         .         .         .         .         .         .         .         .  Ixii 

John  Fitch's  Steamboat,  Philadelphia,  1787 Ixiii 

James  Rumsey's  Steamboat  at  Washington,  D.  C,  1784    ....  Ixiv 

Apollos  Kingsley's  Locomotive,  Hartford,  Conn.,  1798    .         .         .         .  Ixiv 

Robert  Fulton — First  Steamboat,  1803 Ixiv 

"  "      — The  Clermont,  1807         .         .         .         .         .         .         .  Ixv 

Oliver  Evans'  Steam  Engine,  Oructor  Amphibolis,  1804  ....  Ixvi 

First  Small  Railroad  on  Beacon  Hill,  Boston,  1807  ....  Ixxii 

Second  "  "         at  Leiper's  Quarries,  Delaware  Co.,  Pa.,  1809  .  Ixxii 

First  Locomotive  on  Railroad  in  America,  1829        .....  Ixxii 

First  Regular  Railway — B.  &  O.  in  Maryland,  1 830  ....  Ixxiii 

Second  "  "        — South  Carolina,  1830  .         ....  Ixxiii 

Third     "  "        — The  Columbia  (Penna.  Central),  1830  .         .  Ixxiii 

Fourth  "  "        — Philadelphia,  Germantown  &  Norristown,  1830  Ixxiii 

Fifth       "  "        — Camden  &  Amboy,  N.  J.,  1831  .         .         .  Ixxiii 

Sixth      "  "        — Newcastle  &  Frenchtown,  Delaware,  1831  .  Ixxiii 

The  B.  &  O.  Offer  ^4,000  for  the  Best  American  Locomotive,  1831  .  Ixxiv 

Colonel  Long's  First  Engine  on  the  Newcastle  &  Frenchtown  Road,  1831  Ixxiv 

Matthias  Baldwin's  Model  Engine       ........  Ixxvi 

The  B.  &  O.'s  Prize  of  ^4,000  Won  in  1834  by  Phineas  Davis,  of  York,  Pa.  Ixxvii 

Stacey  Costell's  Engine,  1834  ........  Ixxvii 

Thomas  Halloway's  Engine,  1831    ........  Ixxviii 

English  Locomotives  Imporced,  1832        .......  Ixxviii 

The  Old  Ironsides,  1832 .         .         .         .         .         .         .         .         .         .  Ixxix 

Long  &  Norris'  Black  Hawk,  1832.  .......  Ixxx 

William  &  Richard  Norris'  George  Washingtoti,  1836      ....  Ixxxi 

The  Norris  Engine^  1837         .........  Ixxxii 

The  Baldwin  Engine,  1834 Ixxxiii 

Garrett  &  East  wick,  1835 Ixxxv 

The  Samuel  D.  Ingham  .         .         .         .         .         ,         .         .         .         ,  Ixxxv 

The  Bury  Boiler      ...........  Ixxxv 

Henry  R.  Campbell's  Patent    .         . Ixxxvii 

The  Hercules,  1837  .         .         .         .         .         .         ,         ...         .  Ixxxvii 

Joseph  Harrison,  Jr's.,  Connecting  Rod Ixxxviii 

Eastwick  &  Harrison's  Gowan  6^  Marx,  1839 xci 

Eastwick,  Harrison  &  Winans ,        .  xcii 


CONTENTS.  \[[ 

PAGE 

Russian  Engine        ...........    xciii 

Baldwin's  Austrian  Order,  1S40 xciv 

Baldwin's  Patents    ...........    xciv 

Six-wheeled  Engine,  1842         .........    xcv 

Flexible  Beam  Truckj  1842      .........    xcvi 

Central  Railroad  of  Georgia    .........    xcviii 

Levi  Bissell's  Air  Spring         .........    xcviii 

Asa  Whitney  joins  Mr.  Baldwin — the  firm  of  Baldwin  &  Whitney    .         .    xcix 

The  French  &  Baird  Stack c 

The  Grimes  Stack    ...........c 

The  Radley  &  Hunter  Stack    .         .         • c 

The  Cut-off  Valve ci 

Baldwin's  Eight-wheels-connected  "  C "  Engine  .  .  .  .  .  cii 
The  M.  G.  Bright  for  Madison  &  Indianapolis  Railroad  ....  ciii 
The  yohn  Broiigh  for  Madison  &  Indianapolis  Railroad  ....  ciii 
The  Governor  Paine,  first  sixty-miles-an-hour  Engine,  made  by  Baldwin  & 

Whitney,  1849  ...........    civ 

The  Aliffiin,  Blair  and  Indiajta  Engines,  Pennsylvania  Railroad      .         .    cv 
Matthew  Baird  and  M.  W.  Baldwin  partners    ......    cvi 

John  Brandt's  Ten-wheeled  Engine  .......    cvii 

Charles  Whitney,  of  Central  Railroad,  Georgia,  Three  Engines,  Clinton, 

Athens,  and  Sparta  ..........    cviii 

Thomas  Rogers',  of  Rogers'  Locomotive  Works,  Link  Motion  .         ,    cix 

Baldwin's  Variable  Cut-off  Adjustment    .......    cxi 

David  Clark  and  M.  Baldwin's  Feed-water  Heater  .....    cxii 

M.  Baird's  Fire  Brick  Arch  for  Combustion      ......    cxiii 

The  Delano  Grate  ...........    cxiv 

A.  F.  Smith's  Combustion  Chamber  .......    cxiv 

The  Dimpfel  Boiler  ..........    cxiv 

Mr.  Wilder's  New  Boiler  .........    cxv 

The  Bissell  Pony  Truck  ..........    cxvi 

Steel  Tires  first  used  for  Engines — the  Dom  Pedro  II  (Brazilj  Railway 

of  South  America,  1862    .........    cxvi 

Steel  Fire  Boxes  first  used  by  Pennsylvania  Railroad  in  186 1    .         .         .    cxvi 
Horizontal  Cylinders         .  .  .  .         .         .  .  ...  .    cxvii 

Death  of  M.  W.  Baldwin,  1866,  founder  of  Baldwin's  Locomotive  Works    cxvii 
Alexander  Mitchell's  Consolidation  Engine       ......    cxix 

The  Thomas  Iron  Works  Mogul  Engine  .......    cxx 

Steel  Flues  First  Used,  1868,  Pennsylvania  Railroad         ....    cxxi 

Steel  Boilers  First  Used,  1868,  Pennsylvania  Railroad      ....    cxxi 

Straight  Boilers  revived,  1866  ........    cxxi 

Freight  Locomotive,  Consolidation  type,  1873  ......    cxxii 

Freight  and  Passenger  Mogul  type    for    the  Hango-Hyvinge    Railroad, 

Finland    ............    cxxiv 

First  American  Locomotives  for  New  South  Wales  .....    cxxvi 

First  American  Locomotives  for  New  Zealand  and  Victoria      .         .         .    cxxvi 

The  Wootten  Fire  Box  cxxix 

Holly-Gaskill  High  Duty  Pumping  Engine cxxxi 

Worthington  Pumping  Engine cxxxviii 

Highest  Speed  Attained  in  Great  Britain  by  Locomotives,  August  6,  1888    ciii 

Highest  Speed  Record  on  American  Railroads civ 

The  Limit  of  Speed clviii 

Speed  on  the  Rail    .         t         ....*•••         .   clix 


ILLUSTRATIONS  IN  THE  HISTORY  OF  STEAM. 


PAGE 

Portrait  of  James  Watt i 

^OLiPiLE  OF  Hero,  b.  c.  130 xiii 

De  Caus'  Engine  (Steam  Toy),  1615 xv 

Giovanni  Branca's  Steam  Wheel,  1629 xvi 

The  Marquis  of  Worcester's  Engine,  1663   .        .        o        .        .        .  xvii 

Savary's  Engine,  1699 xviii 

Papin's  Engine,  1689 xix 

Newcomen's  Engine,  1705 xxi 

Watt's  Governor xxxiii 

Murdock's  Model  of  Steam  Locomotive,  1785 xxxv 

Portrait  of  George  Stephenson .  xxxvii 

Cugnot's  Engine,  1770 xlviii 

Trevethick's  Steam  Carriage,  1803 xlviii 

Blenkinsop's  Tooth- Wheeled  Locomotive,  1811 xlix 

Brunton's  Stilt  Locomotive,  1813 xlix 

Stephenson's  Locomotive,  1815 1 

"  "  Rocket,"  1829 ,        .  Iv 

Trevethick's  Circular  Railway,  London,  1808 Ixi 

Portrait  of  James  Fulton Ixii 

Fitch's  Steamboat .        .        .        ,  Ixiii 

Fulton's  First  Steamboat,  1803 Ixv 

"         "The  Clermont,"   1807 Ixv 

Oliver  Evans'  "  Oructor  Amphibolis,"   1804 Ixviii 

The  "  Old  Ironsides,"  1832 Ixxix 

Baldwin's  Engine,  1834 Ixxxiii 

Campbell's  First  Design  for  an  Eight- Wheeled  Locomotive,  1836  .  Ixxxviii 

Garrett  &  Eastwick's  "  Hercules,"  1837 xc 

Eastwick  &  Harrison's  "  Gowan  and  Marx,"  1839      ,        .        .        .  xci 

Harrison  &  Winans'  Russian  Engine,  1844 xciii 

Baldwin's  Six- Wheels-Connected  Engine,  1842 xcv 

Flexible  Beam  Truck,  1842,  Elevation  and  Half  Plan      .        .        .  xcvi 

Baldwin's  Eight- Wheels-Connected  "C"  Engine,  1846       .        .        .  cii 

"  Fast  Passenger  Engine,  1848 cv 

Variable  Cut-Off  Adjustment,  1853 cxi 

Horizontal  Cylinders,  1858 ,        .        .        .  cxvli 

Freight  Locomotive,  "Consolidation"  Type,  1870       000.  cxxii 

Wootten  Express  Passenger  Locomotive cxxix 

Holly-Gaskill  Pumping  Engines cxxxi 

Worthington  Pumping  Engines cxxxviii 

(iv3 


THE  HISTORY  OF  STEAM 

AND  ITS  PRACTICAL  APPLIANCES. 


JAMES  WATT 


Uc^^ 


James  Watt,  the  improver  of  the  steam-engine,  was  born  at 
Greenock  in  Renfrewshire,  Scotland,  on  the  19th  of  January,  1736. 
He  was  the  descendant  of  a  family  the  members  of  which,  for  several 
generations,  had  exhibited  no  small  degree  of  ability.  His  great- 
grandfather was  the  proprietor  and  farmer  of  a  small  estate  in  Aber- 
deenshire ;  but  taking  part  in  the  insurrection  headed  by  Montrose, 
he  was  killed  in  one  of  the  battles  then  fought,  and  his  little  property 
Was  confiscated.  This  person's  son,  Thomas  Watt,  was  but  an  in- 
fant at  the  time  of  his  father's  death.     Left  almost  destitute  by  that 

(V) 


vi  HISTORY   OF   THE   STEAM-ENGINE. 

event,  he  was  taken  care  of  by  relations  till  he  grew  up,  when,  man\ 
ifesting  a  decided  taste  for  mathematical  science,  in  which  he  had 
already  attained  great  proficiency,  he  removed  to  Greenock,  and 
settled  there  as  a  teacher  of  navigation,  surveying,  and  general 
mathematics.  In  this  situation  he  acquired  great  reputation,  and 
became  one  of  the  most  respected  and  influential  persons  in  tha 
neighborhood,  filling  for  several  years  the  office  of  baron-bailie,  or 
chief  magistrate  of  the  burgh  of  Crawford's  Dike.  He  died  in 
1734,  at  the  advanced  age  of  ninety-two  years,  and  was  buried  in 
the  West  Churchyard  of  Greenock,  where,  in  the  inscription  on  his 
tombstone,  he  is  styled  "  Professor  of  Mathematics."  He  had  two 
sons,  John  and  James ;  the  plder  of  whom  inherited  his  father's 
mathematical  talent,  and  followed  his  profession,  first  at  Ayr,  and 
afterwards  in  Glasgow,  where  he  also  enjoyed  a  large  business  as  a 
surveyor.  Among  his  qualifications  was  that  of  drawing  with  very 
great  neatness  and  accuracy.  He  died  in  1737,  at  the  age  of  fifty 
years ;  and  a  chart  of  the  course  of  the  river  Clyde  which  he  left 
was  published  a  few  years  afterwards  by  his  younger  brother  James. 
This  James  Watt,  the  father  of  the  great  engineer,  had  settled  in  his 
native  town  of  Greenock,  exercising  his  abilities,  not  in  the  special 
occupation  to  which  his  father  and  elder  brother  had  devoted  them- 
selves, but  in  the  more  general  sphere  of  a  merchant  and  public- 
spirited  citizen.  During  a  quarter  of  a  century  he  held  the  offices 
of  town-councillor  and  magistrate  of  Greenock  ;  and  in  the  discharge 
of  these  offices  he  was  noted  for  his  activity  and  zeal  for  improve- 
ment. It  was  only  in  consequence  of  his  own  refusal  that  he  did 
not  fill  the  chair  of  provost,  or  chief-magistrate,  in  Greenock.  His 
special  occupations  were  those  of  a  block-maker  and  ship-chandler; 
but,  in  addition  to  these,  he  engaged  in  house  and  ship  building  and 
general  trading.  The  failure  of  some  of  his  commercial  speculations 
deprived  him,  long  before  his  death,  of  a  great  part  of  the  fortune 
which  he  had  acquired.  He  died  in  1782,  at  the  age  of  eighty-four, 
having  for  some  years  lived  retired  from  business.  His  wife,  Agnes 
Muirhead,  the  mother  of  the  illustrious  Watt,  was  of  a  very  respect- 
able family;  of  her  disposition,  and  the  character  of  her  mind,  we 
have  no  particular  account. 

The  subject  of  our  memoir  was  the  elder  of  two  sons,  the  only 
children  of  the  Greenock  merchant  and  his  wife.  The  younger,  who 
was  named  John,  had  resolved  to  follow  his  father's  profession,  but 


HISTORY   OF   THE    STEAM-ENGINE.  yJJ 

was  drowned  in  1763  on  a  voyage  from  Greenock  to  America,  at 
the  age  of  twenty-three  years.  James  Watt,  who  was  then  in  his 
twenty-seventh  year,  was  thus  left  the  only  surviving  son. 

watt's    childhood    and     education — SETTLES     IN     GLASGOW 
AS    A   MATHEMATICAL   INSTRUMENT    MAKER. 

Regarding  Watt's  childhood  and  the  course  of  his  early  education, 
we  have  not  much  information.  From  the  extreme  delicacy  of  his 
health  when  a  child,  he  was  able  to  attend  the  public  school  at 
Greenock  only  irregularly  and  at  intervals ;  so  that  much  of  his 
elementary  instruction  was  received  at  home.  His  mother  taught 
him  reading,  and  his  father  writing  and  arithmetic  ;  and  in  his 
confinement  to  the  house,  of  which  his  almost  constant  indisposition 
was  the  cause,  he  acquired  those  habits  of  inquisitiveness  and 
precocious  reflection  so  often  observed  in  feeble-bodied  children, 
"A  gentleman  one  day  calling  upon  his  father,  observed  the  child 
bending  over  a  marble  hearth  with  a  piece  of  colored  chalk  in  his 
hand.  *  Mr.  Watt,'  said  he,  '  you  ought  to  send  that  boy  to  school, 
and  not  allow  him  to  trifle  away  his  time  at  home.'  '  Look  how  my 
child  is  employed  before  you  condemn  him,'  replied  the  father.  The 
gentleman  then  observed  that  the  child  had  drawn  mathematical 
lines  and  circles  on  the  hearth.  He  put  various  questions  to  the 
boy,  and  was  astonished  and  gratified  with  the  mixture  of  intelligence, 
quickness,  and  simplicity  displayed  in  his  answers :  he  was  then 
trying  to  solve  a  problem  in  geometry."  *  In  this  way,  not  by  means 
of  regular  lessons,  but  by  incessant  employment  on  some  subject  of 
interest  or  other.  Watt  in  early  years  acquired  much  of  that  general 
information  for  which  he  was  in  after-life  remarkable.  His  father 
having,  as  a  means  of  amusement,  presented  him  with  a  number  of 
tools  such  as  are  used  in  cabinet-work,  he  became  exceedingly  ex- 
pert in  handling  them,  and  began  to  exhibit  his  mechanical  taste  in 
the  fabrication  of  numerous  toys,  among  which  is  mentioned  a  small 
electrical  machine,  with  a  bottle,  probably  for  a  cylinder. 

An  anecdote  related  of  him  when  he  was  about  fourteen  years  of 
age,  indicates  the  extreme  restlessness  and  activity  of  his  mind  as  a 
boy.  Once  having  accompanied  his  mother  on  a  visit  to  a  friend  in 
Glasgow,  he  was  left  behind  on  her  return.    The  next  time,  however, 


*Aragc'p  Life  of  Watt. 


y[[[  HISTORY   OF   THE   STEAM-ENGINE. 

that  Mrs.  Watt  came  to  Glasgow,  her  friend  said  to  her :  "  You  must 
take  your  son  James  home ;  I  cannot  stand  the  degree  of  excite- 
ment he  keeps  me  in ;  I  am  worn  out  for  want  of  sleep.  Every 
evening  before  ten  o'clock,  our  usual  hour  of  retiring  to  rest,  he 
contrives  to  engage  me  in  conversation,  then  begins  some  striking 
tale,  and,  whether  humorous  or  pathetic,  the  interest  is  so  over- 
powering, that  the  family  all  listen  to  him  with  breathless  attention, 
and  hour  after  hour  strikes  unheeded."  This  wonderful  faculty  of 
story-telling,  which  robbed  the  Glasgow  lady  of  her  sleep.  Watt 
preserved  throughout  his  life  to  a  degree  unparalleled  perhaps 
except  in  Sir  Walter  Scott. 

As  he  advanced  into  youth,  Watt  began  to  occupy  himself  with 
the  sciences.  The  whole  range  of  physics  had  attractions  for  him. 
In  excursions  in  all  directions  from  Greenock,  and  especially  to  the 
banks  of  Loch  Lomond,  he  studied  botany,  entered  eagerly  into  the 
geological  speculations  then  beginning  to  awaken  interest,  and  col- 
lected traditions  and  ballads — all  with  equa4  enthusiasm.  At  home, 
during  his  hours  of  less  robust  health,  he  devoured  books  on 
chemistry  and  general  science,  among  which  was  Gravesande's 
Elements  of  NatiLral  PJiilosophy.  Medicine,  surgery*  and  anatomy 
obtained  their  share  of  his  attention ;  the  detailed  descriptions  of 
diseases  given  in  medical  works  were  familiar  to  him ;  and  he  was 
one  day  detected  carrying  into  his  room  the  head  of  a  child  recently 
dead,  which  he  had  managed  somehow  to  procure,  with  the  intention 
of  dissecting  it.  In  short,  by  incessant  reading  and  mental  activity, 
he  had,  before  he  entered  on  his  nineteenth  year,  acquired  and 
dipfested  a  vast  mass  of  miscellaneous  scientific  information. 

Whether  from  the  prevailing  bend  of  his  genius  towards  me- 
chanical contrivance,  or  from  some  other  cause  connected  with  the 
nature  of  his  father's  trade  in  Greenock,  the  profession  which  Watt 
chose  was  that  of  a  mathematical  and  nautical  instrument  maker. 
To  learn  this  art,  or  rather  to  perfect  himself  in  it,  he  went  to  Lon- 
don in  1755,  and  placed  himself  under  Mr.  John  Morgan,  an  instru- 
ment-maker in  Finch  Lane,  Cornhill.  Thus,  says  M.  Arago,  "  the 
man  who  was  about  to  cover  England  with  engines,  in  comparison 
with  which  the  antique  and  colossal  machine  of  Marly  is  but  a 
pigmy,  commenced  his  career  by  constructing  with  his  own  hands 
instruments  which  were  fine,  delicate,  and  fragile — those  small  but 
admirable  reflecting  sextants  to  which  navigation  is  so  much  in- 


HISTORY   OF   THE   STEAM-ENGINE. 


IX 


debted  for  its  progress."  After  a  residence  of  little  more  than  a 
year  in  London,  his  continued  feeble  health  obliged  him  to  return 
to  Scotland,  where,  in  accordance  with  his  own  wishes  and  the 
advice  of  his  friends,  he  commenced  business  as  a  mathematical 
instrument  maker  in  Glasgow.  The  date  of  his  settlement  in  this 
city,  where  he  was  afterwards  to  work  out  some  of  his  greatest  tri- 
umphs, was  1757,  when  he  had  just  passed  his  twenty-first  year. 
At  first  he  experienced  considerable  opposition,  and  a  great  deal  of 
annoyance — one  of  the  privileged  corporations  of  the  town  regard- 
ing him  as  an  intruder,  and  not  entitled  to  practice  the  business 
which  he  professed,  at  that  time  a  comparatively  rare  one  in  Scot- 
land. Various  means  were  tried  to  soothe  down  the  offended  par- 
ties, but  without  effect;  they  would  not  even  allow  the  young 
tradesman  to  set  up  a  workshop  on  the  smallest  scale.  At  length, 
apparently  through  the  exertions  of  the  friends  of  his  family,  he 
was  rescued  from  the  dilemma  by  the  authorities  of  the  university, 
who  gave  him  a  convenient  room  within  their  precincts,  and  con- 
ferred on  him  the  designation  of  Mathematical  Instrument  Maker  to 
the  College  of  Glasgow,  a  proceeding  which  was  sufficient  to  quash 
all  corporation  enmity.  In  the  workshop  thus  afforded  him.  Watt 
continued  for  a  number  of  years  to  pursue  his  trade  of  making  sex- 
tants, compasses,  etc.,  for  which  articles  he  found  customers  both 
within  and  without  the  walls  of  the  university.  "There  are  still  in 
existence,"  says  M.  Arago,  "some  small  instruments  which  were  at 
this  time  made  entirely  by  Watt's  own  hand,  and  they  are  of  very 
exquisite  workmanship.  I  may  add  that  his  son  has  lately  shown 
me  some  of  his  first  designs,  and  that  they  are  truly  remarkable  for 
the  delicacy  and  precision  of  the  drawing.  It  was  not  without  rea- 
son that  Watt  used  to  speak  with  complacency  of  his  manual  dex- 
terity." This,  as  we  have  seen,  was  a  gift  which  seemed  to  be 
hereditary  in  the  family. 

At  the  time  when  Mr.  Watt  took  up  his  residence  in  Glasgow, 
there  was  a  cluster  of  eminent  men  gathered  together  within  the 
university  such  as  is  rarely  to  be  found.  Adam  Smith  was  Professor 
of  Moral  Philosophy;  Robert  Simson  of  Mathematics;  the  illus- 
trious Black  filled  the  chair  of  Chemistry;  and  Mr.  Dick,  who, 
though  less  known  to  fame,  is  said  to  have  been  a  man  of  great 
powers,  held  the  professorship  of  Natural  Philosophy.  Robison, 
afterwards  so  celebrated  for  his   attainments  in  physical  science. 


jj  HISTORY   OF   THE   STEAM-ENGINE. 

which  he  displayed  as  a  professor  both  in  Edinburgh  and  Glasgow, 
was  then  a  student.  Watt's  position  within  the  college  brought  him 
into  contact  with  all  these  able  men ;  and  the  shop  of  the  young 
mathematical  instrument  maker  soon  became  a  lounging-place  for 
both  professors  and  students — the  former  of  whom  found  in  him  a 
man  equal  to  themselves  in  acquirements,  and  of  a  remarkable 
originality  of  mind;  the  latter,  a  good-natured  and  willing  assistant 
in  their  speculations  and  researches  in  physics.  "I  had  always," 
says  Professor  Robison,  referring  to  those  days  when  he  first  became 
acquainted  with  Watt,  "a  great  relish  for  the  natural  sciences,  and 
particularly  for  mathematical  and  mechanical  philosophy.  When  I 
was  introduced  by  Drs.  Simson,  Dick,  and  Moor  to  Mr.  Watt,  I  saw 
a  workman,  and  expected  no  more ;  but  was  surprised  to  find  a 
philosopher,  as  young  as  myself,  and  always  ready  to  instruct  me. 
I  had  the  vanity  to  think  myself  a  pretty  good  proficient  in  my 
favorite  study,  and  was  rather  mortified  at  finding  Watt  so  much 
my  superior.  Whenever  any  puzzle  came  in  the  way  of  us  students, 
we  went  to  Mr.  Watt.  He  needed  only  to  be  prompted;  for  every- 
thing became  to  him  the  beginning  of  a  new  and  serious  study,  and 
we  knew  that  he  would  not  quit  it  till  he  had  either  discovered  its 
insignificancy  or  made  something  of  it.  He  learned  the  German 
language  in  order  to  peruse  Leopold's  Theatrum  Macldnanmi.  So 
did  I,  to  know  what  he  was  about.  Similar  reasons  made  us  both 
learn  the  Italian  language.  When  to  his  superiority  of  knowledge 
is  added  the  naive  simplicity  and  candor  of  Mr.  Watt's  character,  it 
is  no  wonder  that  the  attachment  of  his  acquaintances  was  strong. 
I  have  seen  something  of  the  world,  and  I  am  obliged  to  say  I  never 
saw  such  another  instance  of  general  and  cordial  attachment  to  a 
person  whom  all  acknowledged  to  be  their  superior.  But  that 
superiority  was  concealed  under  the  most  amiable  candor,  and  a 
liberal  allowance  of  merit  to  every  man.  Mr.  Watt  was  the  first  to 
ascribe  to  the  ingenuity  of  a  friend  things  which  were  nothing  but 
his  own  surmises,  followed  out  and  embodied  by  another.  I  am  the 
more  entitled  to  say  this,  as  I  have  often  experienced  it  in  my  own 
case." 

This  and  similar  accounts  enable  us  to  figure  Mr.  Watt  during  his 
early  residence  in  Glasgow — a  young,  amiable,  and  ingenious  man, 
a  great  favorite  with  professors  and  students,  occupied  during  the 
greater  part  of  the  day  in  his  workshop,  but  constantly  engaged  in 


HISTORY   OF   THE   STEAM-ENGINE. 


XI 


the  evening  in  some  profound  or  curious  question  in  mathematics 
or  physical  science;  quite  aware  of  all  that  was  going  on  in  the 
scientific  world,  and  taking  an  interest  in  all  new  discoveries,  par- 
ticularly those  of  his  friend  Dr.  Black  in  chemistry.  As  a  remark- 
able instance  of  the  extent  of  his  theoretical  research,  and  of  his 
perseverance  in  whatever  undertaking  struck  his  fancy,  it  is  men- 
tioned that  although  he  had  no  ear  for  music,  and  could  never,  all 
his  life,  distinguish  one  note  from  another,  or  derive  pleasure  from 
any  musical  performance,  he  astonished  all  his  friends  by  construct- 
ing an  organ,  which,  besides  exhibiting  numerous  ingenious  me- 
chanical improvements,  was  particularly  admired  by  musicians  for  its 
greatly  superior  powers  of  harmony.  His  only  guide  in  this  diffi- 
cult achievement  must  have  been  the  Harmonies  of  Dr.  Smith,  of 
Cambridge,  a  work  treating  of  some  of  the  extreme  problems  of 
acoustics,  but  so  profound  and  obscure,  that  few  persons  in  the 
kingdom  could  have  understood  a  page  of  it. 

In  the  year  1763,  Mr.  Watt  married  his  cousin,  Miss  Miller,  who 
is  described  as  a  person  of  much  wit  and  accomplishment,  with  great 
sweetness  of  temper.  At  the  same  time  he  removed  from  his  apart- 
ments in  the  college  to  a  house  in  town,  in  which  he  continued  his 
profession,  enlarging  it,  however,  so  as  to  include  engineering.  He 
accordingly  began  to  be  consulted  in  the  construction  cf  canals, 
bridges,  and  other  works  of  large  dimensions  requiring  science  and 
skill.  In  the  midst  of  these  engineering  avocations,  a  circumstance 
occurred  which  exercised  a  more  important  influence  upon  his 
career  than  any  of  them.  In  the  winter  of  1763-64,  Mr.  Anderson, 
who  had  succeeded  Dr.  Dick  as  Professor  of  Natural  Philosophy, 
and  who  is  still  remembered  as  the  founder  of  the  Andersonian 
University,  Glasgow,  finding  that  a  small  model  of  Newcomen's 
steam-engine,  which  he  had  among  his  apparatus,  would  not  work, 
sent  it  to  Mr.  Watt  for  repair.  The  subject  of  steam-machinery  had 
several  times  before  come  under  Mr.  Watt's  notice.  His  friend  Mr, 
Robison  had,  in  1759,  broached  to  him  the  idea  of  applying  steam- 
power  to  wheel-carriages  ;  and  in  1761-62,  he  had  occupied  himself 
with  various  experiments  on  a  Papin's  Digester,  with  a  view  to 
measure  the  force  of  steam.  These  discussions  and  experiments, 
however,  terminated  in  no  particular  result;  and  it  was  Professor 
Anderson's  model  of  Newcomen's  engine  that  begot  in  Watt's  mind 
the  germ  of  those  ideas  respecting  the  use  of  steam-power  which 


2^JJ  HISTORY   OF   THE   STEAM  ENGINE, 

have  led  to  such  gigantic  consequences.  As  Newcomen's  engine 
represents  the  point  of  progress  to  which  steam-machinery  had  been 
brought  before  Watt  appHed  himself  to  the  subject,  this  seems  the 
proper  place  for  introducing  a  sketch  of  the  history  of  steam-power 
up  to  that  period.  The  little  black  model  on  the  instrument-maker's 
table  was  the  condensed  epitome,  as  it  were,  of  all  that  the  world 
knew  of  steam-power  before  that  time ;  in  the  brain  of  the  young 
newly-married  instrument-maker,  bending  by  candlelight  over  the 
model,  lay,  as  yet  undeveloped,  all  that  the  steam-engine  has  since 
become. 

HISTORY    OF    THE   STEAM-ENGINE    BEFORE   THE   TIME   OF   WATT, 

Steam,  or,  as  they  called  it,  "  water  transformed  into  air  by  the 
action  of  fire,"  was  of  course  known  to  the  ancients,  and  was  used 
for  various  ordinary  purposes  in  the  arts.  The  first  description, 
however,  of  the  application  of  steam  as  a  mechanical  power  occurs 
in  the  writings  of  Hero,  a  Greek  of  Alexandria,  who  lived  in  the 
third  century  before  Christ,  This  writer,  whose  attainments  in 
science  were  very  great  for  his  age,  describes  a  toy  called  the 
,^olipile,  the  purpose  of  which  is  to  produce  a  rotatory  motion  by 
the  action  of  steam.  The  best  familiar  illustration  of  the  appearance 
of  such  an  apparatus,  in  one  of  its  simplest  forms,  would  be  one  of 
those  turnstiles,  with  four  horizontal  spokes,  which  are  sometimes 
placed  in  by-paths.  Were  one  of  these  revolving  stiles  made  of 
iron,  and  hollow  throughout,  with  a  hole  in  the  corresponding  side 
of  each  of  the  spokes,  and  were  the  upright  shaft  to  be  fixed  into  a 
socket  beneath,  entering  a  boiler,  then  the  steam  rushing  up  the 
shaft  and  along  the  four  spokes  would  hiss  out  in  four  jets  at  the 
side  openings,  and  the  whole  would,  owing  to  the  force  of  reaction, 
whirl  round  in  the  opposite  direction. 

Here,  therefore,  nearly  two  thousand  years  ago,  we  find  steam 
applied  to  produce  a  rotatory  motion.  By  connecting  the  simple 
rotatory  apparatus  above  described  with  additional  machinery,  mills 
could  be  driven,  and  other  important  mechanical  effects  produced. 
Indeed,  the  construction  of  rotatory  steam-engines  has,  in  recent 
times,  occupied  much  attention;  and,  under  the  name  of  Barker's 
Mill,  the  principle  of  the  ^Eolipile  has  been  turned  to  account — the 
reaction  caused  by  the  escape  of  steam  having  been  made  in  some 
instances  to  do  the  work  of  six  or  eight,  or  even  fifteen  horses. 


HISTORY   OF   THE   STEAM-ENGINE, 


Xlll 


The  principle  of  the  JEoVipile,  however,  and. of  the  rotatory  engines 
which  are  modifications  of  it,  is  evidently  different  from  that  of 
steam-engines  usually  so  called,  in  which  the  power  consists  not  in 
the  mere  reaction  caused  by  steam  violently  escaping  into  the  atmo- 
sphere, but  in  the  prodigious  expansive  force  of  steam  itself  Water, 
when  converted  into  steam  by  the  application  of  heat  under  the 
ordinary  pressure  of  the  atmosphere,  occupies,  it  is  well  known,  1728 
times  its  original  bulk;  in  other  words,  a  cubic  inch  of  water  is,  on 
its  conversion  into  steam,  expanded  so  as  to  fill  a  space  of  a  cubic 
foot.  This  is  nearly  eight  times  as  great  as  the  expansive  force  of 
gunpowder.  Now,  if  by  any  means  we  could  catch  water  in  the  act, 
as  it  were,  of  passing  into  steam,  so  as  to  obtain  the  use  of  the  enor- 
mous expansive  force  for  our  own 
purposes,  it  is  evident  that  we 
could  produce  most  powerful 
effects  by  it.  To  do  this — to  catch 
water  in  the  act  of  passing  into 
steam,  and  turn  the  expansive  force 
to  account — is  the  purpose  of 
steam-engines  properly  so  called. 

Even  this  use  of  the  expansive 
force  of  steam  was  in  some  degree 
known  to  the  ancients.  Often,  as 
M.  Arago  observes,  in  casting  the 
fine  metal  statues  for  which  ancient 
art  is  so  famous,  a  drop  of  water 
or  other  liquid  would  be  left  enclosed  in  the  plaster  or  clay  moulds 
when  the  molten  metal  was  poured  in;  and  the  consequence  would 
be  an  explosion,  and,  in  many  cases,  a  fearful  accident,  from  the 
instantaneous  conversion  of  the  enclosed  drop  of  liquid  into  steam. 
Arguing  from  such  instances,  the  ancient  naturalists  accounted  for 
earthquakes  and  submarine  explosions  on  a  similar  principle,  by 
supposing  the  sudden  vaporization  of  a  mass  of  water  by  volcanic 
heat.  Nor  were  the  ancients  afraid  of  handling  the  power  which 
they  thus  recognized.  In  the  images  of  the  ancient  gods  were  con- 
cealed crevices  containing  water  with  the  means  of  heating  it;  and 
tubes  proceeding  from  these  crevices  conducted  the  steam,  so  as  to 
make  it  blow  out  plugs  from  the  mouths  and  foreheads  of  the  images 
with  loud  noise  and  apparent  clouds  of  smoke.     A  more  ingenious 


THE    ^OLIPILE   OF    HERO     OF 
ALEXANDRIA,    B.    C.    I3O. 


XIV 


HISTORY   OF   THE    STEAM  ENGINE. 


device  still,  and  which  represents  the  utmost  extent  to  which  the 
ancients  carried  their  use  of  the  expansive  force  of  steam,  is  one 
described  by  Hero,  the  purpose  of  which  seems  likewise  to  have 
been  priestly  imposition.  To  accomplish  this  trick,  Hero  directs 
vessels  half  full  of  wine  to  be  concealed  inside  of  two  figures,  in 
the  shape  of  men  standing  on  each  side  of  an  altar.  From  these 
vessels,  tubes,  in  the  form  of  bent  siphons,  with  the  short  end  in  the 
wine,  proceed  along  the  extended  arms  of  the  figures  to  the  tips  of 
their  fingers,  which  are  held  over  the  flame  of  the  sacrifice.  Other 
tubes  proceed  from  the  same  vessels  downwards,  through  the  feet 
of  the  figures,  communicating  through  the  floor  with  the  altar  and 
the  fire.  "  When,  therefore,"  says  Hero,  "you  are  about  to  sacrifice, 
you  must  pour  into  the  tubes  a  few  drops,  lest  they  should  be  injured 
by  heat,  and  attend  to  every  joint,  lest  it  leak;  and  so  the  heat  of  the 
fire,  mingling  with  the  water,  will  pass  in  an  aerial  state  through 
these  tubes  to  the  vases  inside  the  figures,  and,  pressing  on  the  wine, 
make  it  to  pass  through  the  bent  siphons,  until,  as  it  flows  from  the 
hands  of  the  living  creatures,  they  will  appear  to  sacrifice  as  the 
altar  continues  to  burn."  Here  we  have  the  expansive  force  of 
steam  employed  directly  to  raise  a  liquid,  by  pressure,  above  its 
natural  height. 

From  the  time  of  Hero  down  to  the  beginning  of  the  sixteenth 
century  no  advance  appears  to  have  been  made  in  the  application 
of  steam-power.  It  would  appear  that  as  early  as  1543  a  Spanish 
captain  named  Blaxo  de  Garay  showed  a  steamboat  in  the  harbor 
of  Barcelona  of  his  own  invention  :  it  is  said  that  this  was  on  the 
principle  of  the  ^olipile.  Solomon  de  Caus,  a  Frenchman  of 
Normandy,  who,  after  a  residence  in  England,  where  he  was 
employed  in  designing  grottos,  fountains,  etc.,  for  the  palace  of 
the  Prince  of  Wales,  afterwards  Charles  I.,  at  Richmond,  returned 
to  the  continent,  and  published  an  account  of  these  and  other 
inventions  at  Frankfort  in  the  year  16 15.  De  Caus's  steam 
invention  is  a  modification,  in  a  more  patent  and  distinct  form, 
of  the  last-mentioned  artifice  of  Hero.  A  hollow  copper  globe 
is  filled  to  the  extent  of  two-thirds  or  thereby  with  water,  through 
a  funnel-shaped  pipe,  which  enters  it,  and  Avhich  is  furnished  with 
a  stop-cock.  Besides  this  pipe,  another  descends  nearly  to  the 
bottom  of  the  globe,  so  as  to  have  its  termination  beneath  the 
water.     It  is  likewise  furnished  with  a  stop-cock,  and  its  nozzle  is 


HISTORY   OF   THE   STEAM-ENGINE. 


XV 


small.     If  now  the  vessel  be  placed  over  a  fire,  with  the  stop-cock 

of  the  first  pipe  shut,  and  that  of  the  other  open,  it  is  evident  that 

when  the  water  begins  to  boil,  the  steam  being  enclosed,  will  press 

down     the     water,    and 

compel  it  to  rush  up  the 

second  pipe,   forming   a 

jet. 

Such  is  the  steam  toy 
of  De  Caus,  upon  which 
many  French  writers 
have  founded  the  claim 
that  steam  should  be 
considered  a  French 
invention.  If,  however, 
the  merit  of  a  man,  with 
regard  to  an  invention 
with  the  origin  of  which 
he  is  concerned,  is  to  be 
measured  by  his  own 
perception  of  its  impor- 
tance, the  merit  of  Solo- 
mon de  Caus,  with  re- 
gard to  steam-machinery, 
cannot  be  compared  with 
that  of  the  Marquis  of 
Worcester  (known  in 
political  history  as  the 
Earl  of  Glamorgan),  who, 
in  his  Century  of  Inven- 
tions, published  in  1663, 
describes  "an  admirable 
and  most  forcible  way 
to  drive  up  water  by 
fire,  not  by  drawing  or 
sucking  it  upward,"  but 

by  a  method  according  to  which  "one  vessel  of  water  rarefied 
by  fire  driveth  up  forty  vessels  of  cold  water."  What  value  the 
marquis  attached  to  this  invention  appears  from  the  striking  lan- 
guage he  uses  with  regard  to  other  modifications  of  it.     Of  one  he 


DE  CAUS,  A.  D.  16 1 5. 


XVI 


HISTORY   OF   THE    STEAM-ENGINE. 


says:  "I  call  this  a  semi-omnipotent  engine,  and  do  intend  that  a 
model  thereof  be  buried  with  me."  He  also  describes  a  water-work 
capable,  he  says,  of  raising  water  with  the  utmost  facility  to  the 
height  of  a  hundred  feet,  and  which  will,  therefore,  "drain  all  sorts 
of  mines,  and  furnish  cities  with  water  though  never  so  high 
seated."  This  he  pronounces  "the  most  stupendous  work  in  the 
whole  world — an  invention  which  crowns  his  labors,  rewards  his 
expenses,  and  makes  his  thoughts  acquiesce  in  the  way  of  further 
inventions." 

In  1629  Giovanni  Branca,  an  Italian  machinist,  invented  and  pub- 


I   ^ 


L      iNCA,    1629. 


lished  a  highly  suggestive  contribution  to  steam  discovery.  This 
represents  the  operation  of  pounding,  the  pestles  being  acted  on  by 
pulleys  and  cog-wheels,  set  in  motion  by  a  jet  of  steam  issuing  from 
a  pipe  against  the  vane  of  a  horizontal  wheel.  This  was  the  first 
practical  steam-engine. 

It  is  ascertained  that  the  Marquis  of  Worcester  had  actually  con- 
structed a  steam  model  appara^tus.  Although,  however,  it  would 
thus  seem  that  steam-power,  in  one  of  its  most  imposing  forms,  was 
in  actual  operation  so  early  as  1656,  the  invention  does  not  appear 
to  have  taken  root;  and  it  is  not  till  1699,  upwards  of  thirty  years 
after  the  Marquis  of  Worcester's  death,  that  we  find    the  steam- 


HISTORY   OF   THE   STEAM-ENGINE. 


XVll 


engine  again  pressed  on  public  notice.  In  that  year  Captain  Thomas 
Savary  exhibited  to  the  Royal  Society  a  model  of  an  engine  for 
draining  mines,  and  raising  water  to  great  heights.  The  difference 
between  the  Marquis 
of  Worcester's  inven- 
tion and  Savary's  con- 
sisted in  this,  that 
whereas  "  the  mar- 
quis's model  appears 
to  have  been  placed 
on  or  below  the  level 
of  the  water  to  be 
raised,  so  that  the 
water  was  forced  up 
solely  by  the  elastic 
force  of  the  steam,  Sa- 
vary, on  the  other  hand, 
erected  his  engine  at 
a  height  of  nearly  thir- 
ty feet  above  the  level 
of  the  water." 

The  improvement 
of  Savary  consists  in 
combining  the  force 
of  atmospheric  suction, 
as  it  is  usually  called, 
with  that  of  steam- 
pressure;  using  the 
first  to  raise  the  water 
thirty  feet,  and  then 
the  other  to  raise  it 
thirty  feet  or  more 
additional;  and  when 
it  is  considered  that, 
in  the  actual  working 


THE  MARQUIS  OF  WORCESTER  ENGINE,   1 663.* 

engine,  there  was  not  only  one  receiver,  but  two,  which  could  be 


*The  Marquis  of  Worcester's  "Water  Commanding  Engine"  was  patented  in  1663, 
but  the  inventor  was  engaged  on  the  mechanical  arrangements  of  it  as  early  as  1647. 


XVUl 


HISTORY  OF  THE   STEAM-ENGINE. 


alternately  filled  with  steam  and  cooled,  so  as  to  prevent  the  loss  of 
time,  the  value  of  the  improvement  will  be  seen  to  be  very  great. 


Fia.i. 


savary's  engine,  1699.* 

Savary  called  his  machine  the  "  Miner's  Friend  ; "  it  seems,  however, 
to  have  been  used  only  for  the  purpose  of  raising  water  in  houses. 

On  page  xvii  is  a  drawing  of  this  engine.  A,  A^  are  two  cold  water  vessels  connected 
by  B,  Bi — the  steam  pipe — with  C,  the  boiler,  set  in  D,  the  furnace.  The  cold  water  ves- 
sels A,  A^,  also  are  connected  with  E,  the  vertical  water  pipe,  by  means  of  F,  F,  con- 
tinuations of  the  same  pipe  conducted  into  and  nearly  touching  the  bottom  of  each  vessel 
A,  A^.  G,  G^  are  two  water  supply  pipes  with  valves,  a,  a^ ,  dipping  into  H,  the  well. 
It  is  obvious  that  by  uniting  these  pipes  and  placing  the  valves  in  the  upper  bend  of 
each,  it  would  be  sufficient  for  a  single  pipe  to  dip  into  the  water  to  be  raised.  On  the 
steam  pipe  B,  B^  is  b,  a  four-way  steam  cock,  operated  by  b'^ ,  its  lever  handle;  and  on 
the  horizontal  portion  of  the  water  pipe  F,  F^  is  c,  a  four  way  water  cock  operated  by 
c^,  its  lever  handle. 

*  In  the  2 1st  volume  of  Philosophical  Transactions,  published  in  1700,  there  is  a  de- 


HISTORY   OF   THE   STEAM-ENGINE. 


XLX 


The  next  great  contribution  to  the  steam- 
engine  came  from  a  French  engineer,  Denis 
Papin,  known  for  other  important  mechanical 
inventions.  His  important  service  to  steam- 
power  consisted  in  the  idea  of  making  it  act 
through  the  cylinder  and  piston.  In  De  Caus's 
and  Savary's  apparatus  the  steam  pressed  di- 
rectly upon  the  surface  of  the  water;  but 
Papin  conceived  the  idea  of  introducing  the 
steam  into  the  bottom  of  the  receiver,  so  as  to 
force  up,  by  its  elasticity,  a  tightly-fitting  plate 
or  piston,  which  would  again  descend  by  the 
pressure  of  the  atmosphere  as  soon  as  the 
steam  beneath  was  condensed.  The  importance 
of  this  modification  can  hardly  be  overrated, 
when  it  is  considered  that  it  amounts  to  the  ap- 
plication of  steam-power  to  produce  the  mo- 
tion of  a  rod  up  and  down  in  a  cylinder.  This 
was  the  great  step,  the  conciliation  of  steam, 
as  it  were,  into  a  regular  moving  power  at  the 
command  of  man ;  and,  as  M.  Arago  observes, 
the  procuring  afterwards,  from  the  strokes  of  the  piston,  the  power 


PAPIN  S  STEAM    AND 
AIR    ENGINE, 
MAY,      1689.* 


scription,  with  an  engraving,  being  "An.  account  of  Mr.  Thomas  Savery's  engine  for 
raising  water  by  the  help  of  fire."  The  engine  may  be  understood  by  the  double  diagram, 
see  page  xviii.  The  drawing  on  the  left  is  the  front  of  the  engine;  that  on  the  right  is  a 
side  view.  A,  is  the  furnace;  B,  the  boiler;  C,  two  cocks  which  convey  the  steam  from 
the  bottom  in  order  to  discharge  it  again  at  the  top ;  D,  the  vessels  which  receive  the 
water  from  the  bottom  in  order  to  discharge  it  again  at  the  top;  E,  valves;  F,  cocks 
which  keep  up  the  water,  while  the  valves  on  occasion  are  cleaned ;  G,  the  force  pipe ; 
H,  the  sucking  pipe ;  and  I,  the  water. 

*  AA  is  a  tube  of  uniform  diameter  throughout,  close  shut  at  the  bottom ;  BB  is  a 
piston-  fitted  to  the  tube ;  DD,  a  handle  fixed  to  the  piston ;  EE,  an  iron  rod  movable 
round  an  axis  F ;  G,  a  spring  pressing  the  cross-rod  EE,  so  that  the  said  rod  must  be 
forced  into  the  groove  H,  as  soon  as  the  piston  with  the  handle  has  arrived  at  such  a 
height  as  that  the  said  groove  H  appears  above  the  lid  II ;  L  is  a  little  hole  in  the 
piston,  through  which  the  air  can  escape  from  the  bottom  of  the  tube  AA,  when  first  the 
piston  is  forced  into  it.  The  use  of  this  instrument  is  as  follows : — A  small  quantity  of 
water  is  poured  into  the  tube  AA,  to  the  depth  of  three  or  four  lines ;  then  the  piston  is 
inserted  and  forced  down  to  the  bottom,  till  a  portion  of  the  water  previously  poured  in 
comes  through  the  hole  L;  then  the  said  hole  is  closed  by  the  rod  MM.  Next  the  lid 
II,  pierced  with  the  apertures  requisite  for  that  purpose,  is  put  on,  and  a  moderate  fire 
being  applied,  the  tube  AA  soon  grows  warm  (being  made  of  thin  metal),  and  the 


XX 


HISTORY   OF   THE   STEAM-ENGINE. 


to  turn  millstones,  or  the  paddles  of  a  steamboat,  or  to  uplift  the 
massy  hammer,  or  to  move  the  huge  clipping  shears — these  were 
but  secondary  problems.  Papin,  however,  did  not  work  out  his 
own  conception — did  not  perceive  all  its  consequences. 

The  next  modification  of  the  steam-engine,  and  its  ultimate  one 
before  it  came  into  the  hands  of  Watt,  consisted,  it  may  be  said,  in 
the  union  of  Savary's  idea  with  that  of  Papin.  The  authors  of  this 
invention — which  may  in  reality  be  considered  as  the  first  working 
steam-engine — were  Thomas  Newcomen,  an  ironmonger,  and  John 
Cawley,  a  glazier,  both  of  Dartmouth,  in  Devonshire.  In  the  year 
1705  these  two  individuals  "constructed  a  machine  which  was  meant 
to  raise  water  from  great  depths,  and  in  which  there  was  a  distinct 
vessel  where  the  steam  was  generated.  This  machine,  like  the  small 
model  of  Papin,  consisted  of  a  vertical  metallic  cylinder,  shut  at  the 
bottom  and  open  at  the  top,  together  with  a  piston  accurately  fitted, 
and  intended  to  traverse  the  whole  length,  both  in  ascending  and 
descending.  In  the  latter,  as  in  the  former  apparatus  also,  when  the 
steam  was  admitted  into  the  lower  part  of  the  cylinder,  so  as  to  fill 
it,  and  counterbalance  the  external  atmospheric  pressure,  the  ascend- 
ing movement  of  the  piston  was  effected  by  means  of  a  counter- 
poise. Finally,  in  the  English  machine,  in  imitation  of  Papin's,  as 
soon  as  the  piston  reached  the  limit  of  its  ascending  stroke,  the 
steam  which  had  impelled  it  was  refrigerated;  a  vacuum  was  thus 
produced,  and  the  external  atmosphere  forced  the  piston  to  de- 
scend." *  The  only  novelty  in  Newcomen's  engine,  over  and  above 
what  had  existed  either  in  Papin's  or  in  Savary's  model,  was  the 
mode  of  condensing  the  steam  in  the  cylinder.  This  was  effected 
not  by  simply  withdrawing  the  heat  from  the  bottom  of  the  cylinder, 
as  Pipin  had  done,  nor  by  dashing  cold  water  on  the  outside  of  it, 
as  in  Savary's  apparatus,  but   in  directing  a  stream  of  cold  water 

water  within  it  being  turned  into  steam,  exerts  a  pressure  so  powerful  as  to  overcome 
the  weight  of  the  atmosphere  and  force  up  the  piston  BB,  till  the  grove  H,  of  the  handle 
DD,  appears  above  the  lid  II,  and  the  rod  EE  is  forced,  with  some  noise,  into  the  said 
groove  by  the  spring  G.  Then  forthwith  the  fire  is  to  be  removed,  and  the  steam  in  the 
thin  metal  tube  is  soon  resolved  into  water,  and  leaves  the  tube  entirely  void  of  air. 
Next  the  rod  EE,  being  turned  round  so  far  as  to  come  out  of  the  groove  H,  and  allow 
the  handle  D  to  descend,  the  piston  BB  is  forthwith  pressed  down  by  the  whole  weight 
of  the  atmosphere,  and  causes  the  intended  movement;  which  is  of  an  energy  great  in 
proportion  to  the  size  of  the  tube. 
*  Arago's  Life  of  Watt. 


HISTORY   OF   THE    STEAM-ENGINE. 


XXI 


into  the  inside  of  the  cylinder  at  every  rise  of  the  piston.  This 
improvement — an  important  one  at  the  time — is  said  to  have  been 
made  by  accident,  from  tlie  circumstance  of  water  once  finding  its  way 
into  the  cylinder  through  a  hole  in  the  piston,  and  astonishing  the 
onlookers  by  its  results.  The  entire  action  of  Newcomen's  engine 
will  be  understood  from  the  annexed  cut,  representing  a  section  of 
if  B  is  the  boiler,  built  over  a  furnace,  and  kept  about  two-thirds 
full  of  water;  the  quantity  of  water  being  regulated  by  means  of 
two  vertical  tubes  with  stop-cocks  (GG),  which  descend  into  the 
boiler,  the  one  to  a  greater  depth  than  the  other,  so  that  when  the 
boiler  contains  its  proper  quantity  of  water,  the  longer  tube  shall 
dip  into  it,  while  the  shorter 
does  not  reach  it.  When  the 
boiler  is  heated,  the  pressure 
of  the  steam  in  its  upper  part 
will,  if  the  proper  quantity  of 
water  be  in  the  boiler,  force 
the  water  up  the  longer  pipe, 
while  only  steam  issues  from 
the  shorter.  Should  both  pipes 
emit  water,  then  it  is  known 
that  the  boiler  is  too  full; 
should  both  emit  steam,  that  it 
is  not  full  enough;  and  the 
supply  can  be  regulated  ac- 
cordingly. Besides  these  ^«7/;^^- 
pipes  there  is  in  the  boiler  a 
safety-valve  (SV),  loaded  so  as 
to  lie  tight  until  the  steam  in 
the  boiler  accumulates  to  a  degree  sufficient  to  force  it  up.  From 
the  boiler  the  steam  passes  through  the  connecting  tube,  guarded 
by  the  regulating-valve  (V),  made  so  as  to  open  and  shut  easily, 
into  the  cylinder  (C).  Up  and  down  in  this  cylinder,  which  is 
open  at  the  top,  moves  the  piston  (P),  attached  by  means  of 
the  piston-rod  (M)  to  a  flexible  chain,  which  is  fastened  to  the 
top  of  the  arch  at  the  end  of  a  beam,  moving  on  the  pivot  (I). 
The  end  of  the  beam  to  which  the  piston-rod  is  attached  is  made 
lighter  than  the  other  end,  so  that  when  the  engine  is  at  rest,  it 
ascends  and  pulls  up  the  piston  to  the  top  of  the  cylinder.     The 


newcomen's  engine,  1705. 


Xxii  HISTORY   OF   THE   STEAM-ENGINE. 

piston  thus  lying  at  the  top  of  the  cylinder,  lets  the  steam  from  the 
boiler  be  admitted  through  the  regulating-valve  (V).  The  steam 
rushing  in  expels  the  air  which  was  in  the  cylinder  through  the 
snifting-valve  (H),  which  is  at  the  bottom  of  the  cylinder,  and  so 
constructed,  that  although  it  permits  the  escape  of  the  air,  it  allows 
none  to  enter.  The  whole  space  of  the  cylinder  underneath  the 
piston  being  now  filled  with  steam,  the  next  operation  is  to  con- 
dense it.  This  is  done  by  turning  a  cock  (R)  in  the  tube  (A),  which 
descends  from  a  cistern  kept  constantly  full  of  cold  water.  The 
water,  tending  to  rise  to  the  height  from  which  it  has  fallen,  spouts 
into  the  cylinder,  striking  against  the  bottom  of  the  piston,  and  fall- 
ing down  in  a  shower  of  drops,  which  cool  the  cylinder  and  con- 
dense the  steam.  This  condensation  of  the  steam  produces  a 
vacuum  in  the  cylinder;  and  the  piston,  pressed  down  by  the 
weight  of  the  atmosphere  outside,  rapidly  descends — the  water 
which  was  thrown  into  the  cylinder  being  carried  off  by  the  long 
ediiction-pipe  which,  having  a  valve  at  its  extremity  opening  only 
outwards,  leads  to  a  cistern  (S),  whence  the  boiler  is  supplied.  The 
descent  of  the  piston  pulls  down  the  piston-rod  and  chain,  and  the 
end  of  the  beam  to  which  they  are  attached.  The  other  end  of  the 
beam  accordingly  rises,  pulling  up  a  chain  which  is  attached  to  the 
pimip-rod  (N),  working  the  pump  by  which  the  mine  is  to  be 
drained.  The  purpose  of  the  smaller  pnmp-rod  working  parallel  to 
N,  is,  by  the  action  of  the  engine,  to  raise  a  portion  of  the  water 
through  the  tube  (EE)  to  the  cistern  from  which  the  water  is  sent 
into  the  cylinder.  The  piston  is  now  at  the  bottom  of  the  cylinder, 
and  would  remain  there  by  the  pressure  of  the  atmosphere  on  its 
upper  surface;  but  by  opening  the  valve  (V),  the  steam  from  the 
boiler  is  admitted  under  it,  and  the  pressure  of  the  atmosphere 
being  thus  counterbalanced,  the  superior  weight  of  the  pump-rod 
end  of  the  beam  causes  it  to  descend,  elevating  the  other  end  with 
the  piston  attached  to  it.  The  cylinder  being  again  filled  with  steam 
as  before,  the  stop-cock  (R)  is  turned,  and  the  water  spouts  in ;  '"he 
steam  is  condensed;  the  piston  descends;  the  pump-rod  rises;  and 
so  on,  stroke  after  stroke.  The  use  of  the  small  tube  (T),  proceed- 
ing from  the  cistern,  is  to  pour  a  little  water  above  the  piston,  to 
keep  it  air-tight. 

As  may  be  supposed,  m.uch  care  and  attention  was  at  first  required 
in  Newcomen's  engine  on  the  part  of  the  person  whose  work  it  was 


HISTORY   OF   THE   STEAM-ENGINE.  xxili 

to  keep  incessantly  turning  the  stopcocks  (V  and  R) ;  the  first  for 
the  admission  of  steam  from  the  boiler,  the  second  for  the  admission 
of  the  cold  water  for  the  condensation  of  the  steam.  The  whole 
action  of  the  machine  depended  on  the  attention  of  the  person  who 
watched  these  two  cocks.  A  curious  accident,  however,  remedied 
this  inconvenience.  A  boy  of  the  name  of  Humphrey  Potter  being 
employed  to  tend  one  of  Newcomen's  engines,  found  the  constant 
watching  so  troublesome  that  he  set  himself  to  contrive  a  way  by 
which  the  cocks  might  be  turned  at  the  right  time,  and  yet  he  might 
enjoy  himself  for  an  hour  or  so  at  a  time  with  the  boys  in  the  street. 
Observing  that  the  particular  moment  at  which  the  valve  (V)  required 
to  be  opened  for  the  admission  of  the  steam  was  that  at  which  the 
pump-rod  end  of  the  beam  was  raised  to  its  highest  and  that  the 
moment  at  which  the  other  cock  (R)  required  to  be  opened  was 
when  the  piston-rod  end  was  at  its  highest,  he  saw  that,  by  attaching 
strings  to  the  stop-cocks,  and  connecting  them  with  various  parts 
of  the  beam,  the  rising  and  falling  of  the  tv/o  ends  would  turn  the 
cocks  regularly  as  was  necessary.  Such  was  the  scogging  or  skulk- 
ing gear  of  the  boy  Potter,  so  called  because  it  enabled  him  to  scog 
or  play  truant  from  his  work,  and  afterwards  improved  by  the  sub- 
stitution of  rods  for  strings.  The  steam-engine  was  now  entirely 
self-working ;  the  only  attendant  necessary  was  the  fireman  to  tend 
the  furnace. 

Such  was  the  atmospheric  engine  of  Newcomen,  used  to  a  con- 
siderable extent  for  the  purpose  of  draining  mines,  and  upon  which 
various  engineers  employed  their  skill  during  the  first  half  of  the 
eighteenth  century,  with  a  view  to  render  it  applicable  to  other 
mechanical  purposes,  such  as  driving  mills,  etc.  Among  those  who 
thus  directed  their  attention  to  the  steam-engine  was  the  celebrated 
Smeaton ;  and  some  of  the  finest  specimens  of  Newcomen's  engine 
were  of  liis  construction.  No  improvement  of  essential  conse- 
quence, however,  was  effected  in  the  steam-engine  until  it  came  into 
the  "hands  of  Watt,  whose  successive  contrivances  to  render  it  "p'er- 
fect  we  now  proceed  to  describe. 

watt's  improvements  on  the  steam-engine  as  a  draining   and 

pumping  machine. 

Watt  was  a  man  with  whom,  to  repeat  the  words  of  Professor 
Robinson,  "  everything  became  the  beginning  of  a  new  and  serious 


j^xiv  HISTORY   OF   THE   STEAM-ENGINE, 

study;"  accordingly,  not  content  with  merely  repairing  Professor 
Anderson's  model,  so  that  it  should  work  as  before  in  presence  of 
the  students  in  the  class-room,  he  devoted  himself  to  the  thorough 
investigation  of  all  parts  of  the  machine  and  of  the  theory  of  its 
action.  Directing  his  attention  first,  with  all  his  profound  physical 
and  mathematical  knowledge,  to  the  various  theoretical  points  in- 
volved in  the  working  of  the  machine,  "  he  determined,"  says  M. 
Arago,  "  the  extent  to  which  the  water  dilated  in  passing  from  its 
liquid  state  into  that  of  steam.  He  calculated  the  quantity  of  water 
which  a  given  weight  of  coal  could  vaporize — the  quantity  of  steam, 
in  weight,  which  each  stroke  of  one  of  Newcomen's  machines  of 
known  dimensions  expended — the  quantity  of  cold  water  which 
required  to  be  injected  into  the  cylinder  to  give  the  descending 
stroke  of  the  piston  a  certain  force — and,  finally,  the  elasticity  of 
steam  at  different  temperatures.  All  these  investigations  would 
have  occupied  the  lifetime  of  a  laborious  philosopher;  whilst  Watt 
brought  all  his  numerous  and  difficult  researches  to  a  conclusion, 
without  allowing  them  to  interfere  with  the  labors  of  his  work- 
shop." 

Leaving  Watt's  theoretical  researches  into  the  mode  and  power 
of  action  by  steam,  let  us  attend  to  the  practical  improvements 
which  he  made  in  the  construction  of  the  engine  itself  Newcomen's 
machine  labored  under  very  great  defects.  In  the  first  place,  the 
jet  of  cold  water  into  the  cylinder  was  a  very  imperfect  means  of 
condensing  the  steam.  The  cylinder,  heated  before,  not  being 
thoroughly  cooled  by  it,  a  quantity  of  steam  remained  uncondensed, 
and,  by  its  elasticity,  impeded  the  descent  of  the  piston,  lessening 
the  power  of  the  stroke.  Again,  when  the  steam  rushed  into  the 
cylinder  from  the  boiler,  it  found  the  cylinder  cold  in  consequence 
of  the  water  which  had  recently  been  thrown  in,  and  thus  a  con- 
siderable quantity  of  steam  was  immediately  condensed  and  wasted, 
while  the  rest  did  not  attain  its  full  elasticity  till  the  cylinder  became 
again  heated  up  to  212  degrees.  These  two  defects — the  imperfec- 
tion of  the  vacuum  created  in  the  cylinder  when  hot  and  the  loss 
of  steam  in  rushing  into  the  cylinder  when  cold — were  sources  of 
great  expense.  Both  defects,  it  will  be  observed,  had  their  origin 
in  the  alternate  heating  and  cooling  of  the  cylinder;  and  yet,  ac- 
cording to  Newcomen's  plan,  this  alternate  heating  and  cooling  was 
inevitable. 


HISTORY   OF   THE   STEAM-ENGINE,  XXV 

Watt  remedied  the  evil  by  a  simple  but  beautiful  contrivance — his 
SEPARATE  CONDENSER.  The  whole  efificacy  of  this  contrivance  con- 
sisted in  his  making  the  condensation  of  the  steam  take  place,  not 
in  the  cylinder,  but  in  a  separate  vessel  communicating  with  the 
cylinder  by  a  tube  provided  with  a  stop-cock.  This  vessel  being 
exhausted  of  air,  it  is  evident  that,  on  the  turning  of  the  stop-cock 
in  the  tube  connecting  it  Avith  the  cylinder,  the  steam  from  the 
cylinder  will  rush  into  it  so  as  to  fill  the  vacuum ;  and  that  this  will 
continue  until  the  steam  be  equally  distributed  through  both  ves- 
sels— the  cylinder  and  the  other.  But  if,  in  addition  to  being  free 
from  air,  the  separate  vessel  be  kept  constantly  cool  by  an  injection 
of  cold  water,  or  other  means,  so  as  to  condense  the  steam  as  fast 
as  it  rushes  in  from  the  cylinder,  it  is  evident  that  all  the  steam  will 
quit  the  cylinder,  and  enter  the  separate  vessel,  to  be  condensed 
there.  The  cylinder  will  be  thus  left  a  perfect  vacuum,  without  hav- 
ing lost  any  of  its  heat  by  the  process  ;  the  piston  will  descend  with 
full  force,  and  when  the  new  steam  rushes  in  from  the  boiler  no  por- 
tion of  it  will  be  wasted  in  reheating  the  cylinder. 

So  far  the  invention  was  all  that  could  be  desired ;  an  additional 
contrivance  was  necessary,  however,  to  render  it  complete.  The 
steam  in  the  act  of  being  condensed  in  the  separate  vessel  would 
give  out  its  latent  heat ;  this  would  raise  the  temperature  of  the 
condensing  water  ;  *  from  the  heated  water  vapor  would  rise,  and 
this  vapor,  in  addition  to  the  atmospheric  air  which  would  be  dis- 
engaged from  the  injected  water  by  the  heat,  would  accumulate  in 
the  condenser  and  spoil  its  efficiency.  In  order  to  overcome  this 
defect,  Watt  attached  to  the  bottom  of  the  condenser  a  common  air- 
pump,  called  the  condejtser  pump,  worked  by  a  piston  attached  to 
the  beam,  and  which,  at  every  stroke  of  the  engine,  withdrew  the 
accumulated  water,  air  and  vapor.  This  was  a  slight  tax  upon  the 
power  of  the  machine,  but  the  total  gain  was  enormous — equivalent 
to  making  one  pound  of  coal  do  as  much  work  as  had  been  done 
by  five  pounds  in  Newcomen's  engine. 

This,  certainly,  was  a  triumph ;  but  Watt's  improvements  did  not 

*The  effect  of  the  latent  heat  of  the  steam  in  heating  the  water  in  the  condenser  may 
be  judged 'of  from  the  fact  that,  if  two  pounds  of  steam  be  condensed  by  ten  pounds  of 
freezing  water,  the  result  will  be  twelve  pounds  of  water  at  the  boiling--^o\v\. ;  in  other 
words,  two  pounds  of  steam  at  212  degrees  contain  latent  heat  sufficient  to  boil  ten 
pounds  of  freezing  water. 


Xxvi  HISTORY  OF  THE   STEAM-ENGINE. 

stop  here.  In  the  old  engine  the  cylinder  was  open  at  the  top,  and 
the  descent  of  the  piston  was  caused  solely  by  the  pressure  of  the 
atmosphere  on  its  upper  surface.  Hence  the  name  of  Atmosplieric 
Engine,  which  was  always  applied  to  Newcomen's  machine,  the  real 
moving  power  being  not  the  steam,  which  served  no  purpose  ex- 
cept to  produce  the  necessary  vacuum,  but  the  atmosphere  pressing 
on  the  piston  with  the  force  (supposing  the  vacuum  to  be  complete) 
of  about  fifteen  pounds  to  a  square  inch.  This  was  attended  with 
the  inconvenience  that,  the  atmosphere  being  cold,  tended  to  cool 
the  inside  of  the  cylinder  in  pushing  down  the  piston,  which,  of 
course,  caused  a  waste  of  steam  at  every  stroke.  The  inconvenience 
was  avoided,  and  the  whole  engine  improved,  by  entirely  shutting 
out  the  atmospheric  action  and  employing  the  steam  itself  to  force 
down  the  piston.  This  was  accomplished  in  the  following  way.  In- 
stead of  a  cylinder  open  at  the  top  Watt  used  one  with  a  close 
metallic  cover,  with  a  nicely-fitted  hole  in  it,  through  which  the 
greased  piston-rod  could  move  freely,  while  it  did  not  allow  the 
passage  of  air  or  steam.  Thus  the  cylinder  was  divided  into  two 
chambers  quite  distinct  from  each  other — that  above  and  that  below 
the  piston.  Now,  in  addition  to  the  former  communications  be- 
tween the  cylinder  and  the  boiler  and  condenser,  a  tube  was  made 
to  connect  the  boiler  with  the  upper  chamber,  so  as  to  introduce 
steam  above  the  piston.  This  steam,  by  its  elastic  force,  and  no 
longer  the  atmosphere  by  its  pressure,  drove  down  the  piston  when 
the  vacuum  had  been  formed  by  the  condensation  of  the  steam  be- 
neath ;  and  as  soon  as  the  descending  stroke  was  complete,  the 
turning  of  a  cock  could  admit  steam  from  the  boiler  equally  into 
both  chambers,  thus  restoring  the  balance  and  enabling  the  piston 
to  ascend,  as  before,  by  the  mere  counterpoise  of  the  beam.  The 
engine  with  this  improvement  Watt  named  the  Modified  Engine ;  it 
was,  however,  properly  the  first  real  i'^m/zz-engine ;  for  in  it,  for  the 
first  time,  steam,  besides  serving  to  produce  the  vacuum,  acted  as 
the  moving  force.  In  this  substitution  of  steam  as  the  moving  force 
instead  of  the  atmosphere,  there  was,  moreover,  this  peculiar  advan- 
tage— that  whereas  the  force  of  the  atmosphere  was  uniform,  and 
could  in  no  case  exceed  fifteen  pounds  on  every  square  inch  of  the 
piston's  surface,  the  force  of  the  steam  could,  within  certain  limits, 
be  varied. 

Another  improvement  less  striking  in  appearance,  but  of  value  in 


HISTORY   OF   THE   STEAM-ENGINE.  xxvii 

economizing  the  consumption  of  fuel,  was  the  enclosing  of  the 
cylinder  in  a  jacket  or  external  drum  of  wood,  leaving  a  space  be- 
tween which  could  be  filled  with  steam.  By  this  means  the  air  was 
prevented  from  acting  on  the  outside  of  the  cylinder  so  as  to  cool 
it.  A  slight  modification  was  also  necessary  in  the  mode  of  keep- 
ing the  piston  air-tight.  This  had  been  done  in  Newcomen's  engine 
by  water  poured  over  the  piston ;  but  in  the  closed  cylinder  this  was 
obviously  impossible ;  the  purpose  was  therefore  effected  by  the  use 
of  a  preparation  of  wax,  tallow  and  oil  smeared  on  the  piston-rod 
and  round  the  piston-rim. 

The  improvements  which  we  have  described  had  all  been  thor- 
oughly matured  by  Mr.  Watt  before  the  end  of  1765,  two  years 
after  his  attention  had  been  called  to  the  subject  by  the  model  of 
Newcomen's  engine  sent  him  for  repair.  During  these  two  years 
he  had  been  employing  all  his  leisure  hours  on  the  congenial  work, 
performing  his  experiments  in  a  delft  manufactory  at  the  Broomielaw 
quay,  where  he  set  up  a  working  model  of  his  engine,  embodying 
all  the  new  improvements  and  having  a  cylinder  of  nine  inches 
diameter.  One  would  anticipate,  as  M.  Arago  remarks,  that  when 
the  fact  of  the  construction  of  so  promising  and  economical  an  en- 
gine was  made  generally  known,  "  it  would  immediately  displace,  aS 
a  draining  apparatus,  the  comparatively  ruinously  expensive  machines 
of  Newcomen.  This,  however,  was  far  from  being  the  case.  Watt's 
grand  invention  and  most  felicitous  conception,  that  steam  might  be 
condensed  in  a  vessel  quite  separated  from  the  cylinder,  was  com- 
pleted in  the  year  1765  ;  and  in  two  years  scarcely  any  progress  was 
made  to  try  its  applicability  upon  the  great  scale."  Watt  himself 
did  not  possess  the  necessary  funds  for  that  purpose.  "At  length," 
says  Lord  Brougham,  "  he  happily  met  with  Dr.  Roebuck,  a  man  of 
profound  scientific  knowledge  and  of  daring  spirit  as  a  speculator. 
He  had  just  founded  the  Carron  iron-works,  not  far  from  Glasgow, 
and  was  lessee,  under  the  Hamilton  family,  of  the  Kinneil  coal- 
works."  Such  a  man,  so  extensively  employed  in  engineering,  was 
precisely  the  person  to  introduce  Watt's  invention  into  practice ; 
and  accordingly  a  partnership  was  formed  between  him  and  Watt, 
according  to  the  terms  of  which  he  was  to  receive  two-thirds  of  the 
profits  in  return  for  the  outlay  of  his  capital  in  bringing  the  new 
machines  into  practice.  A  patent  was  taken  out  by  the  partners  in 
1769,  and  an  engine  of  the  new  construction,  withj,an  eighteen-inch 


XXviii  HISTORY   OF   THE   STEAM-ENGINE. 

cylinder,  was  erected  at  the  Kinneil  coal-works  with  every  prospect 
of  complete  success,  when,  unfortunately.  Dr.  Roebuck  was  obliged 
by  pecuniary  embarrassments  to  dissolve  the  partnership,  leading 
Watt  with  the  whole  patent,  but  without  the  means  of  rendering  it 
available. 

watt's     OCCUPATIONS     AS    A    GENERAL    ENGINEER HIS    PARTNERSHIP 

WITH    MR.    BOULTON    OF   SOHO. 

Watt,  ralther  than  apply  to  the  money-lenders  for  funds,  which 
they  would  very  probably  have  been  glad  to  invest  in  so  hopeful  a 
speculation,  devoted  himself  for  some  time  exclusively  to  the  proper 
business  of  his  profession  as  a  civil  engineer,  allowing  his  steam- 
engine  model  to  lie  like  mere  lumber  in  the  Broomielaw  delft-work. 
Between  the  years  1769  and  1774  he  was  employed  in  various 
engineering  enterprises  of  great  importance — "  the  extensive  opera- 
tions of  which  Scotland  then  became  the  scene  giving,"  says  Lord 
Brougham,  "  ample  scope  to  his  talents.  He  was  actively  engaged 
in  the  surveys  and  afterwards  in  the  works  for  connecting  by  a  canal 
the  Monkland  coal-mines  with  Glasgow.  He  was  afterwards  em- 
iployed  in  preparing  the  canal,  since  completed  by  Mr.  Rennie,  across 
'the  Isthmus  of  Crinan ;  in  the  difficult  and  laborious  investigations 
for  the  improvement  of  the  harbors  of  Ayr,  Greenock  and  Glasgow; 
■in  improving  the  navigation  of  the  Forth  and  Clyde,  and  in  the 
Campbelton  Canal,  besides  several  bridges  of  great  importance,  as 
those  of  Hamilton  and  Rutherglen."  *  "  What  Johnson  said  of 
Goldsmith  may  with  equal  justice  be  applied  to  Watt — '  he  touched 
nothing  that  he  did  not  adorn.'  In  the  course  of  his  busy  surveys 
his  mind  was  ever  .bent  on  improving  the  instruments  he  employed, 
or  in  inventing  others  to  facilitate  or  correct  his  operations.  During 
the  period  of  which  we  have  been  speaking  he  invented  two  microm- 
eters, for  measuring  distances  not  easily  accessible,  such  as  arms 
of  the  sea.  Five  years  after  the  invention  of  these  ingenious  instru- 
ments one  Mr.  Green  obtained  a  premium  for  an  invention  similar 
to  one  of  them,  from  the  Society  of  Arts,  notwithstanding  the 
evidence  of  Smeaton  and  other  proofs  that  Watt  was  the  original 
contriver. 

*  Memoir  > of  Watt  in  Xord  Brougham's  Men  of  Letters  of  the  Reign  of  Georgs 
JII. 


HISTORY   OF   THE   STEAM-ENGINE. 


XXIX 


"In  1773  the  importance  of  an  inland  navigation  in  the  northern 
part  of  Scotland  between  the  eastern  and  western  seas  became  so 
great  that  Mr.  Watt  was  employed  to  make  a  survey  of  the  Cale- 
donian Canal  and  to  report  on  the  practicability  of  connecting  that 
remarkable  chain  of  lakes  and  valleys.  These  surveys  he  made 
and  reported  so  favorably  of  the  practicability  of  the  undertaking 
that  it  would  have  been  immediately  executed  had  not  the  forfeited 
lands  from  which  the  funds  were  to  be  derived  been  restored  to  the-ir 
former  proprietors.  This  great  national  work  was  afterward  exe- 
cuted by  Mr.  Telford  on  a  more  magnificent  scale  than  had  been 
originally  intended." 

At  the  end  of  the  year  1773  Watt  was  left  a  widower  by  the  death 
of  his  wife  in  Glasgow  while  he  was  absent  on  his  survey  of  the 
Caledonian  Canal.  Two  children,  a  son  and  a  daughter,  survived 
their  mother.  This  event  would  probably  have  the  effect  of  with- 
drawing his  attention  still  more  from  his  steam  inventions.  For 
five  years  his  patent  "  for  methods  of  lessening  the  consumption  of 
steam  and  consequently  of  fuel  in  the  steam-engine  "  had  been  run- 
ning without  bringing  him  any  returns,  the  dissolution  of  his  part- 
nership with  Dr.  Roebuck  having  thrown  the  entire  risks  of  intro- 
ducing the  new  machine  into  practice  upon  himself,  and  either  his 
cautious  temperament  or  his  actual  want  of  means  preventing  him 
from  abandoning  the  certainties  of  his  profession  for  the  sake  of 
pushing  his  steam-engine  into  public  notice.  This  indifference  is 
certainly  in  itself  not  entitled  to  be  considered  a  merit ;  we  point  it 
out  merely  as  characteristic. 

At  length,  in  1774,  Mr.  Watt  entered  into  a  partnership  most  for- 
tunate for  himself  and  for  the  world.  This  was  with  Mr.  Matthew 
Boulton,  of  the  Soho  Foundry,  near  Birmingham — g,  gentleman  of 
remarkable  scientific  abilities,  of  liberal  disposition  and  of  unbounded 
enterprise,  who,  having  his  attention  called  to  the  improvements  on 
Newcomen's  steam-engine  effected  by  the  Glasgow  surveyor,  im- 
mediately formed  a  connection  with  him,  sharing  the  patent,  as  Dr. 
Roebuck  had  formerly  done. 

Almost  the  first  business  of  the  partners  was  to  procure  a  pro- 
longation of  Watt's  patent,  which,  having  commenced  in  1769,  had 
but  a  few  years  to  run.  Whether  because  the  value  of  Watt's  im- 
provements had,  by  the  mere  course  of  time,  become  more  generally 
recognized  than  at  first,  or  because  the  enthusiasm  with  which  so 


xxx 


HISTORY   OF   THE   STEAM-ENGINE. 


well-known  an  individual   as   Mr.  Boulton  patronized  them,  roused 
many  parties  to  a  sense  of  their  importance,  it  was  only  after  a  very 
keen  opposition  in  Parliament  that  the  extension  of  the  patent  for 
twenty-five  years  was  obtained.     At  the  head  of  those  who  opposed 
the  renewal  of  the  patent  in  the  House  of  Commons  was  the  cele- 
brated Edmund   Burke;  the  opponents  out  of  the  house  were  the 
engineers  and  miners  whom  the  patent  would  prevent  from  employ- 
ing the  engine  without  paying  the  inventor  for  permission  to  do  so. 
The  extension  of  the  patent  having  been  procured,  the  partners 
began  to  construct,  at  their  manufactory  at  Soho,  draining-machines 
of  the    largest    dimensions,   which    immediately  supplanted   New- 
comen's  engines  in  all  the  mining  districts.     The  bargain  which  the 
partners  made  with  those  mine  proprietors  who  applied  for  permis- 
sion to  use  the  improved  engine  was  certainly  the  most  reasonable 
that  could  have  been  expected.     They  stipulated  for  receiving  '■  a 
third  part  of  the  value  of  the  coal  saved  by  the  use  of  the  new  engine." 
Yet  this  agreement  brought  ample  profits  to  the  partners,  as  may  be 
judged  from  the  fact,  that  the  proprietors  of  the  single  mine  of  Chase- 
water  in  Cornwall,  where  three  pumps  were  employed,  commuted 
the  proposed  tliird  of  the  coal  saved  into  ;!^2500  a  year  for  each  of  the 
engines.     Thus  the  saving  effected  by  one  engine  amounted  to  at 
least  ;^7500,  which  had  been  expended  formerly  in  waste  fuel.     As 
there  was  a  possibility  that,  if  the  mine  proprietors  had  been  left  to 
estimate  for  themselves  the  value  of  the  saving,  they  might  cheat  the 
partners  of  their  fair  dues,  Watt  rendered  himself  independent  of 
them  by  confiding  the  duty  of  rendering  an  account  to   a  meter, 
invented  on  purpose,  and  which,  kept  in  a  box  under  a  double  lock, 
registered  every  stroke  of  the  engine. 

As  the  engine  was  one  of  large  dimensions,  it  was  scarcely  possible 
to  pirate  it  secretly ;  but  so  numerous  were  the  attempts  made  to 
plagiarise  it,  or,  by  ingenious  ways,  to  infringe  the  patent  right,  that 
Messrs.  Watt  and  Boulton  were  almost  perpetually  engaged  in  law- 
suits to  defend  their  property.  In  several  cases,  the  opposition 
which  Mr.  Watt  experienced  on  account  of  his  defending  his  rights 
amounted  to  positive  persecution — to  attacks  on  his  character. 
These  attacks,  however,  failed ;  and  in  their  lawsuits  the  partners 
were  uniformly  successful.  "  I  have  been  so  beset  with  plagiaries," 
says  Mr.  Watt  in  one  of  his  letters,  "  that  if  I  had  not  a  very  distinct 
recollection  of  my  doing  it,  their  impudent  assertions  would  lead  me 


HISTORY   OF   THE   STEAM-ENGINE.  ^xxi 

to  doubt  whether  I  was  the  author  of  any  improvement  on  the 
steam-engine." 

As  the  foundry  at  Soho  was  one  of  the  largest  establishments  in 
Great  Britain,  Watt's  new  position,  as  a  partner  with  Mr.  Boulton, 
was  one  of  great  wealth  and  consequence.  He  had  hardly  entered 
upon  it,  when,  in  the  year  1775,  after  two  years  of  widowhood,  he 
married  Miss  Macgregor,  the  daughter  of  a  rich  Glasgow  merchant. 

The  first  consequence  of  the  introduction  of  Watt's  improved 
steam-engine  into  practice  was  to  give  an  impulse  to  mining  specu- 
lations. New  mines  were  opened ;  and  old  mines,  which  could  not 
be  profitably  worked  when  taxed  with  such  a  consumption  of  fuel 
for  draining  as  Newcomen's  engines  required,  now  yielded  a  return. 
This  was  the  only  obvious  consequence  at  first.  Only  in  mines, 
and  generally  for  the  purpose  of  pumping  water,  was  the  steam- 
engine  yet  used ;  and  before  it  could  be  rendered  applicable  to  other 
purposes  in  the  arts — before  it  could  promise,  even  to  the  most 
sanguine  expectation,  to  perform  such  a  universal  part  in  machinery 
as  that  which  we  now  witness  it  performing — the  genius  of  Watt 
required  once  again  to  stoop  over  it,  and  bestow  on  it  new  creative 
touches. 

IMPROVEMENTS   BY  WATT,  RENDERING  THE   STEAM-ENGINE  APPLICABLE 
FOR    GENERAL    PURPOSES. 

Any  one,  on  considering  the  steam-engine,  will  perceive  that  the 
original  motion  in  it,  and  the  source  of  all  others,  is  that  of  the 
piston  up  and  down  in  the  cylinder.  It  is  by  connecting  the  piston- 
rod  with  other  pieces  of  machinery  through  a  beam  that  the  work 
is  done.  Now,  in  the  draining-engine  the  piston-rod  was  attached 
to  the  beam  by  a  flexible  chain.  Where  the  purpose  was  the  mere 
pumping  of  water,  the  inconvenience  of  this  was  not  so  great ;  but 
to  render  the  steam-engine  useful  for  other  purposes,  it  was  necessary 
to  do  away  with  the  flexible  chain,  and  connect  the  piston-rod  with 
the  end  of  the  beam  by  some  rigid  communication.  Watt  effected 
this  by  a  beautiful  invention,  known  as  the  parallel  motion.  At  the 
end  of  the  beam  of  a  steam-engine  of  the  construction  common 
some  years  ago,*  may  be  observed  a  curious  jointed  parallelogram, 

*  In  engines  of  modern  construction  the  beam  is  seldom  used ;  the  crank-rod  is  jointed 
directly  to  the  piston-rod,  and  the  piston-rod  is  made  to  preserve  its  parallelism  by  means 
of  a  cross-head  moving  in  guides. 


XXXll 


HISTORY   OF   THE    STEAM-ENGINE. 


with  the  piston-rod  attached  to  one  of  its  angles.  When  the  engine 
is  in  action,  if  the  movements  of  this  parallelogram  be  watched 
attentively,  it  will  be  perceived  that  while  three  of  the  angles  of  the 
parallelogram  move  in  small  circular  arcs,  the  fourth — that  to  which 
the  piston-rod  is  attached — is  so  pulled  upon  by  opposite  forces, 
that  although  tending  to  move  in  a  curve,  it  moves  in  a  straight 
line.  This  result  depends  on  a  very  recondite  mathematical  prin- 
ciple ;  the  contrivance,  however,  practically,  is  one  of  the  most 
simple  imaginable.  "  I  myself,"  says  Watt,  speaking  of  his  first  trial 
of  the  parallel  motion,  "  have  been  much  surprised  with  the  regularity 
of  its  action.  When  I  saw  it  in  movement,  it  afforded  me  all  the 
pleasure  of  a  novelty,  and  I  had  quite  the  feeling  as  if  I  had  been 
examining  the  invention  of  another." 

Another  improvement,  which,  in  point  of  the  additional  power 
gained,  was  more  important  than  the  parallel  motion,  and  which 
indeed  preceded  it  in  point  of  time,  was  the  Double-acting  Engine. 
In  the  steam-engine,  so  far  as  we  have  yet  described  it,  the  whole 
force  consisted  in  the  downward  stroke ;  in  the  depression  of  the 
piston  in  Newcomen's  engine  by  the  atmosphere;  and  in  Watt's 
improved  engine  by  the  steam  admitted  into  the  upper  chamber 
of  the  cylinder.  When  the  piston  had  reached  the  bottom  of  the 
cylinder,  it  arose  again  by  the  mere  counterpoise  of  the  other  end  of 
the  beam,  just  as  the  lighter  end  of  a  weighing-beam  ascends  when 
the  pressure  which  kept  it  down  is  removed.  Watt  remedied  this 
defect,  by  giving  the  piston  an  upward  as  well  as  a  downward 
stroke ;  that  is,  by  employing  the  steam  to  push  up  the  piston  as 
well  as  to  push  it  down.  After  the  whole  cylinder  is  first  filled  with 
steam,  a  communication  is  opened  between  the  upper  chamber  and 
the  condenser ;  thus  the  steam  in  the  upper  chamber  is  condensed, 
and  a  vacuum  is  formed,  upon  which  the  elasticity  of  the  steam  in 
the  lower  chamber  pushes  up  the  piston.  This  is  the  ascending 
stroke.  To  procure  the  descending  stroke,  a  communication  is 
next  opened  between  the  lower  chamber  of  the  cylinder  and  the 
condenser ;  by  this  means  a  vacuum  is  formed  below  the  piston ; 
steam  is  then  admitted  into  the  upper  chamber,  and  its  elasticity 
pushes  the  piston  down.  And  thus,  by  the  alternate  admission  and 
condensation  of  steam  above  and  below  the  cylinder,  the  double 
action  is  procured,  giving  a  double  power  for  the  same  size  of 
cylinder,  and  there  is  no  longer  any  necessity  for  one  end  of  the 
beam  being  heavier  than  the  other. 


HISTORY  OF  THE  STEAM-ENGINE. 


XXXIU 


Besides  the  double-stroke  engine  Mr,  Watt  also  indicated  an  im- 
provement, which  he  did  not  fully  carry  out,  but  which  has  since 
been  attended  with  results  so  surprising  as  regards  the  economizing 
of  the  steam  that  its  utility  ranks  as  high  as  that  of  the  separate 
condenser.  This  consists  in  shutting  off  the  steam  from  the  boiler 
before  the  whole  length  of  the  stroke,  whether  upward  or  downward, 
is  completed,  leaving  the  quantity  admitted  to  perform  the  rest  of 
the  stroke  by  its  expansive  force.  When  the  steam  is  shut  off  at 
half-stroke  it  is  found  that  the  efficacy  of  the  steam  is  increased  by 
considerably  more  than  a  half;  at  quarter-stroke,  the  same  quantity 
of  steam — and,  therefore,  the  same  quantity  of  fuel — will  do  more 
than  twice  the  work  it  would  do  if  steam  were  admitted  during  the 
whole  stroke. 

Watt  had  thus  gone  as  far  as  it  was  possible  to  go  in  increasing 
the  power  of  the  steam  -  engine. 
*^  Power,  however,"  observes  M.  Ar- 
ago,  "  is  not  the  only  element  of  suc- 
cess in  the  labors  of  industry.  Regu- 
larity of  action  is  of  no  less  impor- 
tance ;  and  what  degree  of  regularity 
is  to  be  expected  from  a  moving 
power  which  is  procured  from  the 
fire,  under  the  influence  of  the  poker 
and  shovel,  and  supplied  by  coals  of 
very    different    qualities :    under    the 

influence,  too,  of  workmen  often  far  from  intelligent  and  almost  al- 
ways inattentive  ?  We  should  expect  that  the  propelling  steam  would 
be  sometimes  superabundant ;  that  hence  it  would  rush  into  the  cylin- 
der with  greater  rapidity,  so  making  the  piston  work  more  rapidly  ac- 
cording as  the  fire  was  more  powerful,  and  from  such  causes  great  ine- 
qualities of  movement  appear  almost  inevitable."  Watt's  genius  pro- 
vided a  remedy  for  this  by  an  ingenious  application  of  an  apparatus 
called  the  governor,  which  should  regulate  the  quantity  of  steam  ad- 
mitted from  the  boiler  into  the  cylinder.  The  nature  of  this  piece  of 
mechanism  will  be  understood  by  the  annexed  figure.  A  spindle  or 
upright  log,  with  a  pulley  on  its  lower  part  by  which  it  is  moved, 
receiving  motion  through  a  strap  attached  to  the  shaft  or  axle,  has 
two  balls,  which  revolve  along  with  it.  These  balls,  by  the  means 
of  joints,  may  be  separated  considerably  from,  or  brought  nearer  to, 


watt's    governor. 


XXxiv  HISTORY   OF   THE   STEAM-ENGINE. 

the  spindle.  Two  levers  are  connected  with  the  rods  to  which  the 
balls  are  attached,  having  a  free  movement  on  other  levers  similar  in 
length  and  thickness,  but  which  meet  in  a  metallic  ring  movable  up- 
wards and  downwards  on  the  spindle.  Immediately  above  the  ring 
a  lever  is  placed  transversely  across  the  ring,  fixed  at  one  point,  but 
connected  to  another  which  is  bent,  to  the  end  of  which  the  throttle- 
valve  of  the  steam-pipe  is  attached.  This  valve,  it  may  be  here 
noticed,  is  intended  to  regulate  the  supply  of  steam,  allowing  it  to 
escape  when  horizontal  in  full  stream  and  obstructing  it  proportion- 
ately as  it  assumes  a  vertical  direction.  When,  therefore,  the  engine 
acts  with  increased  speed  or  velocity,  and  the  main  shaft  to  which 
this  spindle  is  attached  is  revolved  with  a  proportionate  degree  of 
rapidity,  the  balls  will  recede  to  a  greater  distance  from  each  other, 
and  accordingly  the  levers,  acting  on  the  throttle  valve,  will  raise  it 
so  as  to  diminish  the  flow  of  steam.  But  if  the  shaft  revolves  slowly, 
the  spindle  also  having  its  velocity  regulated  by  it,  the  balls  will 
naturally  approximate  each  other,  and  the  lever  will  now  so  act  on 
the  valve  as  to  throw  it  completely  open,  and  thereby  permit  the 
steam  to  enter  in  a  full  current  to  the  cylinder  and  accelerate  the 
motion.  Such  is  the  efficacy  of  this  apparatus  that  by  its  means  a 
§team-engine  may  be  made  to  give  motion  to  a  clock  which  shall 
keep  good  time.  "  It  is  this  regulator  of  Watt's,"  says  M.  Arago, 
*'  and  a  skilful  employment  of  fly-wheels,  which  constitute  the  true 
secret  of  the  astonishing  perfection  of  the  manufactures  of  our  epoch. 
It  is  this  which  confers  on  the  steam-engine  a  working  movement 
which  is  wholly  free  from  irregularity  and  by  which  it  can  weave 
the  most  delicate  fabrics  as  well  as  communicate  a  rapid  movement 
to  the  ponderous  stones  of  a  flour-mill." 

To  describe  all  the  other  inventions  of  a  minor  kind  connected 
with  the  steam-engine  which  came  from  the  prolific  genius  of  Watt 
would  occupy  too  much  space.  Rotary  engines,  already  alluded 
to  in  the  present  History,  and  which  have  engaged  much  attention  of 
late  years,  were  not  only  thought  of  by  Watt,  but  actually  con- 
structed ;  "  he  subsequently  abandoned  them,  however,  not  because 
they  did  not  work,  but  because  they  appeared  to  him  decidedly  in- 
ferior, in  an  economical  point  of  view,  to  machines  of  double  powers 
and  rectilineal  oscillations."  The  earliest  results  of  his  improvements 
in  the  application  of  steam  will  be  found  in  Cugnot's  (French) 
"  Road  Steam  Engine,"  1770,  page  xlviii ;  and  about  ten  years  later, 


HISTORY   OF   THE   STEAM-ENGINE. 


XXXV 


in  1784,  William  Symington,  one  of  the  early  inventors  of  the 
steamboat,  was  similarly  occupied  in  Scotland  in  endeavoring  to 
perfect  the  steam  carriage  ;  but,  chiefly  because  of  the  bad  roads  in 
Scotland  at  that  period,  he  had  to  abandon  it. 

The  same  year  William  Murdock,  the  friend  and  assistant  of  Watt, 
constructed  his  model  of  a  locomotive  at  Redruth,  in  Cornwall, 
It  was  of  small  dimensions,  standing  little  more  than  afoot  high; 
and  it  was  until  recently  in  the  possession  of  the  son  of  the  inventor, 
The  annexed  section  will  give  an  idea  of  the  arrangements  of  this 
machine. 

It  acted  on  the  high- 
pressure  principle,  the 
boiler  being  heated  by 
a  spirit  lamp.  Small 
though  the  machine 
was,  it  went  so  fast  on 
one  occasion  that  it 
fairly  outran  the  speed 
of  the  inventor.  It 
was  a  dark  night,  and 
Murdock  set  out  alone 
to  try  his  experiment. 
Having  lit  his  lamp, 
the  water  shortly  be- 
gan  to   boil,   and   off 

started  the  engine  with  the  inventor  after  it.  He  soon  heard  dis- 
tant shouts  of  despair.  It  was  too  dark  to  perceive  objects ;  but  he 
shortly  found,  on  following  up  the  machine,  that  the  cries  proceeded 
from  the  worthy  pastor  of  the  parish,  who,  going  towards  the  town 
on  business,  was  met  on  this  lonely  road  by  the  hissing  and  fiery 
little  monster,  which  he  subsequently  declared  he  had  taken  to  be 
the  Evil  One  iJi  propria  persona.  No  further  steps,  however,  were 
taken  by  Murdock  to  embody  his  idea  of  a  locomotive  carriage  in 
a  more  practical  form. 

To  express  by  any  ordinary  terms  in  our  language  the  advantages 
resulting  from  Watt's  improvements  of  the  steam-engine  would  be 
altogether  impossible.  We  have  only  to  look  abroad  on  the  world 
and  see  what  mighty  applications  of  this  wonderful  engine  are 
everywhere  visible.  Steam  navigation,  railway  travelling,  automatic 
factory  labor,  steam  printing,  mining  and  hundreds  of  other  arts 


murdock's  model  of   a  locomotive 

GINE,    1784. 


EN- 


XXXVl 


HISTORY   OF   THE   STEAM-ENGINE. 


have  been  brought  to  their  present  state  by  means  of  Watt's 
discoveries.  In  its  adaptation  to  mills  and  factories  steam  is 
doubtless  more  costly  than  water-power ;  but,  being  independent  of 
situation  or  season,  it  is  in  general  circumstances  preferable.  Its 
placid  steadiness,  and  the  ease  with  which  it  may  be  managed,  are 
also  great  recommendations  in  its  favor.  As  a  motive-power  in  the 
arts,  steam  takes  the  lead  of  all  others,  and,  viewing  it  as  an 
economizer  of  labor,  it  must  assuredly  be  pronounced  the  greatest 
help  of  mankind.  What  electricity  is  doing  or  will  do  in  the  future 
is  not  pertinent  to  our  present  history. 

It  is  in  consequence  of  the  improved  mechanical  arrangements 
and  employment  of  inanimate  forces  in  Great  Britain  that  that  com- 
paratively small  country  has  hitherto  been  enabled  to  manufacture 
goods  cheaper,  and  with  greater  profit,  than  can  be  done  by  the 
largest  and  most  populous  countries  in  which  mechanism  is  imper- 
fect and  labor  performed  exclusively  by  living  agents. 

The  profits  of  manufactures  so  produced  spread  their  beneficial 
influence  over  the  whole  mass  of  society,  every  one  being  less  or 
more  benefited.  Thus  almost  all  the  luxuries  and  comforts  of  life, 
all  the  refinements  of  social  existence,  may  be  traced  to  the  use  of 
tools  and  machinery.  Machinery  is  the  result  of  mechanical  skill, 
and  mechanical  skill  is  the  result  of  experience  and  a  long  course 
of  investigations  into  the  workings  of  principles  in  nature  which  are 
hidden  from  the  inattentive  observer.  Much  of  the  present  mechan- 
ical improvement  is  also  owing  to  the  pressure  of  necessities,  or 
wants,  which  have  always  a  tendency  to  stimulate  the  dormant 
powers  of  man.  What  are  to  be  the  ultimate  limits  and  advantages 
of  mechanical  discoveries  no  one  can  foresee.  The  investigation  of 
natural  forces  is  yet  far  from  being  finished.  Every  day  discloses 
some  new  scientific  truth,  which  is  forthwith  impressed  into  the  ser- 
vice of  mankind  and  tends  to  diminish  the  sum  of  human  drudgery. 
In  this  manner  are  we  usefully  taught  that  the  study  of  nature  forms 
a  never-failing  source  of  intellectual  enjoyment  and  that  "  Knowl- 
edge IS  Power." 


THE   LIFE   OF   GEORGE   STEPHENSON. 


When  we  see  a  railway  train  drawn  by  a  locomotive  at  the  rate 
of  forty  miles  an  hour  and  carrying  as  many  as  five  hundred  pas- 
sengers, how  little  are  we  apt  to  think  that  this  marvel  of  science 
and  art  is  due  mainly  to  two  men,  who,  in  the  outset  of  their  career, 
occupied  an  obscure  position — James  Watt  and  George  Stephenson, 
one  a  Scotsman,  the  other  a  native  of  the  north  of  England,  and 
both  affording  bright  examples  of  what  may  be  done  in  adverse  cir- 
cumstances by  dint  of  well-directed  labor,  united  with  that  degree 
of  prudence  without  which  ingenuity  and  toil  are  usually  in  vain. 
Of  James  Watt  and  the  steam-engine  we  have  already  treated. 
Here  we  have  to  speak  of  Stephenson — plain  old  George,  with  his 
Northumbrian  burr — the  perfecter  of  the  locomotive,  but  for  whom 

(xxxvii) 


XXXviii  HISTORY   OF   THE   STEAM-ENGINE. 

it  might  have  been  long  before  we  should  have  seen  a  train  running 
at  the  speed  which  now  astonishes  everybody. 

George  had  a  very  humble  beginning.  His  father,  Robert 
Stephenson,  with  his  wife  Mabel,  were  a  decent  couple,  living  at  a 
small  colliery  village,  called  Wylan,  situated  on  the  north  bank  of 
the  Tyne,  about  eight  miles  from  Newcastle.  Here  "  old  Bob,"  as 
Robert  was  usually  styled  by  the  neighbors,  was  employed  as  fire- 
man to  the  engine  which  pumped  Water  from  the  coal-pit,  an  em- 
ployment of  a  toilsome  kind,  but  requiring'  no  great  skill,  and  ac- 
cordingly requited  by  the  wage  of  a  common  laborer.  It  is  said 
that  Bob  was  descended  from  a  Scottish  family  which  had  emigrated 
into  Northumberland  and  had  some  pretensions  to  be  of  a  superior 
class.  But  now  the  family  had  settled  down  as  hand  workers,  a  po- 
sition in  no  respects  dishonorable,  for  in  every  department  of  honest 
labor,  no  matter  how  humble,  there  is  a  dignity  which  nothing  can 
overshadow.  Lowly  as  was  his  situation  in  life,  Robert  Stephenson 
had  tastes  of  no  grovelling  kind.  Amiable  in  disposition,  he  was 
fond  of  animals,  and  loved  to  tell  stories  of  one  kind  or  other, 
which  made  him  a  great  favorite  with  young  persons.  Mabel,  his 
wife,  good,  "  canny  Mabel,"  is  reported  to  have  been  a  woman  of  a 
thoughtful,  nervous  temperament,  and  it  is  not  unlikely  that,  in  this 
as  in  many  other  instances,  the  mother  communicated  the  impress 
of  her  character  to  her  children. 

Robert  Stephenson  had  six  children,  of  whom  George,  the  hero 
of  our  story,  was  the  second,  born  June  9,  178 1.  The  lot  of  the 
family  was  to  work,  and  work  they  did.  We  do  not  know  whether 
the  father,  with  all  his  tastes,  had  any  wish  to  give  his  children  a 
fair  country  education.  Perhaps  there  were  no  schools  near  at 
hand,  but  be  this  as  it  may,  Bob's  children,  like  their  neighbors  in 
like  circumstances,  were  left  entirely  to  themselves  in  the  way  of 
book-learning.  When  George  was  about  eight  years  of  age  his 
father  removed  to  another  colliery  concern  at  Dewley  Burn,  where 
he  filled  a  similar  situation — that  of  shovelling  in  coal  to  a  furnace 
which  kept  a  steam-engine  at  work.  It  requires  no  stretch  of 
imagination  to  fancy  Bob  here  laboring  daily  in  front  of  a  glowing 
fire,  with  a  big  shovel  in  hand,  clothed  in  coarse  blue  woollen 
trousers  and  shirt  and  wiping  the  drops  of  perspiration  from  his  face 
with  a  bunch  of  coarse  tow.  Could  any  one,  looking  at  that  toil- 
ing, perspiring  man,  have  supposed  that  he  was  the  father  of  one 


HISTORY   OF   THE   STEAM-ENGINE.  XXXIX 

of  England's  great  men  ?  Bob,  indeed,  had  not  the  sHghtest  no- 
tion himself  that  he  had  a  son  who  was  to  come  to  honor,  and  how 
could  he  ? 

Shortly  after  coming  to  Devvley  Burn  George  was  put  to  work, 
for  he  was  eight  years  old  and  it  was  believed  he  could  earn  some- 
thing to  help  on  the  family.  A  job  was  found  for  him ;  it  was  to 
herd  a  few  cows,  for  which  light  duty  he  was  paid  twopence  a  day. 
We  are  now,  as  it  were,  introduced  to  George.  He  comes  on  the 
stage  as  a  bare-legged  herd-boy,  driving  cows,  chasing  butterflies 
and  amusing  himself  by  making  water-mills  with  reeds  and  straws, 
and  even  going  the  length  of  modelling  small  steam-engines  with 
clay.  In  these  pursuits  we  have  a  glimpse  of  his  mechanical  turn. 
Often  we  see  that  boys  take  a  bent  towards  what  first  excites  their 
fancy.  Brought  up  among  coal-pits  and  pumps,  and  wheels  and 
engines,  it  was  not  surprising  that  his  mind  should  have  a  bias  to 
mechanics.  Some  boys,  indeed,  are  so  dull  or  heedless  that  they 
may  see  the  most  curious  works  of  art  without  giving  them  any  sort 
of  attention.  But  that  was  not  George  Stephenson's  way.  He 
pried  into  every  mechanical  contrivance  that  came  under  notice  and 
acquired  a  knack  of  making  things  with  no  other  help  than  an  old 
knife.  There  was  the  poor  boy's  genius.  He  did  not  stare  at 
things  stupidly  or  with  an  affected  air  of  indifference ;  neither  did  he 
pretend  to  take  an  interest  in  works  of  art  in  order  to  appear  clever. 
He  liked  to  work  out  his  own  ideas  in  his  simple  way,  without  a 
thought  of  results.  From  being  a  herd-boy  he  was  promoted  to 
lead  horses  when  ploughing,  hoe  turnips  and  do  other  farm  work, 
by  which  he  rose  from  twopence  to  fourpence  a  day.  He  might 
have  advanced  to  be  an  able-bodied  ploughman,  but  his  tastes  did 
not  lie  in  the  agricultural  line.  What  he  wished  was  to  be  em- 
ployed about  a  colliery,  so  as  to  be  among  bustle  of  wheels,  gins 
and  pulleys.  Accordingly,  quitting  farm  work,  he  got  employment 
at  Dewley  Burn  to  drive  a  gin-horse,  by  which  change  he  had 
another  rise  of  twopence  a  day,  his  wages  being  now  three  shillings 
a  week.  In  a  short  time  he  went  as  gin-horse  driver  to  the  colliery 
of  Black  Callerton,  and  as  this  was  two  miles  from  the  parental 
home,  he  walked  that  distance  morning  and  evening.  This  walk, 
however,  was  nothing  to  George,  who  was  getting  to  be  a  big,  stout 
boy,  fond  of  rambling  about  after  birds'  nests  and  keeping  tame 
rabbits  and  always  taking  a  part  in   country  sports.     His  next  rise 


xl  HISTORY   OF   THE   STEAM-ENGINE. 

was  to  act  as  an  assistant  fireman  to  his  father  at  Dewley.  Gladly 
he  accepted  this  situation,  for  besides  that  he  was  allowed  a  shilling 
a  day,  he  looked  to  being  promoted  to  be  engineman,  which  now, 
in  his  fourteenth  year,  was  the  height  of  his  ambition.  George  did 
not  long  remain  here.  The  coal-pit  was  wrought  out  and  deserted, 
and  the  workmen  and  apparatus  were  removed  to  a  colliery  at  Jolly's 
Close,  a  few  miles  distant.  The  Stephenson  family  removed  with 
the  others,  and  now  occupied  a  cottage  of  only  a  single  apartment, 
situated  in  a  row  of  similar  dwellings,  with  a  run  of  water  in  front 
and  heaps  of  debris  all  around. 

In  this  miserably  confined  cottage  there  were  accommodated  the 
father  and  mother  and  six  children,  some  of  them  pretty  well  grown 
up,  and  as  all  helped  by  their  work  there  was  nothing  like  poverty 
in  the  household.  George  and  his  elder  brother  James  were  as- 
sistant firemen,  two  younger  boys  performed  some  humble  labor 
about  the  pit  and  two  girls  assisted  their  mother  in  household 
affairs.  The  total  earnings  of  the  father  and  sons  amounted  to  from 
35.?.  to  40.y.  a  week.  As  this  was  equal  to  about  ^100  per  annum, 
we  are  entitled  to  say  that  on  that  sum  old  Bob  ought  to  have 
brought  up  his  family  respectably  and  given  them  at  least  the  ele- 
ments of  education.  But  in  this,  as  in  thousands  of  cases,  little 
else  was  thought  of  than  to  consume  the  whole  weekly  earnings  in 
a  coarse  kind  of  plenty,  leaving  chance  or  the  parish  to  provide  for 
the  future.  No  doubt,  humble  as  it  was,  this  was  a  most  extrava- 
gant way  of  living,  and  it  is  obviously  by  such  improvidence  that 
many  of  the  manual  laboring  classes  keep  themselves  ever  on  the 
brink  of  poverty.  The  only  excuse  we  can  find  for  Bob  and  Mabel 
is  that  they  did  not  know  any  better  and,  deprived  of  suitable  house 
accommodation,  had  perhaps  no  heart  to  aspire  to  a  more  economic 
mode  of  life.  Nor  should  we  fail  to  remember  that  unless  school 
instruction  is  obtruded  in  some  shape  or  other  on  colliery  villages 
and  rural  hamlets  the  residents  can  scarcely  be  blamed  for  their  ig- 
norance. Recent  statutes  and  arrangements  have  probably  done 
much  to  remedy  this  social  defect  among  the  Northumbrian  colliers, 
and  their  children  must  in  many  respects  be  better  looked  to  than 
was  the  fortune  of  their  predecessors.  From  whatever  cause,  the 
want  of  education  was  a  serious  disadvantage  to  the  young  Stephen- 
sons.  Not  one  of  them  was  taught  to  read.  George,  at  fifteen  years 
of  age,  when  working  as  assistant  fireman,  and  forming  one  of  a 


HISTORY   OF   THE   STEAM-ENGINE.  xll 

family  who  were  earning  about  a  hundred  a  year,  and  paying  no 
house-rent,  did  not  know  a  letter.  To  one  with  much  natural 
sagacity  and  an  ambition  to  improve  in  circumstances  we  cannot 
easily  conceive  a  more  dreary  condition.  Let  any  one  picture  to 
himself  the  situation  of  a  friendless  lad,  totally  uneducated,  living 
in  a  colliery  village,  and  then  try  to  conceive  by  what  force  of  cir- 
cumstances that  lad  was  to  attain  to  eminence  in  wealth  and  station 
and  as  a  benefactor  to  mankind.  In  vain  we  make  the  effort,  yet 
we  shall  see  by  what  simple  means  Providence  brings  out  great  re- 
sults, which  no  man  can  possibly  discover  by  the  most  penetrating 
foresight. 

Every  man,  no  matter  how  lowly  his  lot,  may  be  said  to  have  a 
choice  of  two  paths.  He  may  fall  in  with  the  multitude  of  those 
who  seek  immediate  self-indulgence  and  take  no  thought  of  the 
future ;  or,  shrinking  from  this  too  common  routine,  he  may,  in  the 
face  of  untold  difficulties,  make  a  sacrifice,  for  the  sake  of  rnoral 
and  intellectual  improvement,  with  which  not  unusually  comes  an 
improvement  in  circumstances.  We  are  now  called  on  to  notice 
which  of  the  two  paths  was  taken  by  George  Stephenson.  He 
chose  immediate  sacrifice,  and  lived  to  thank  God  for  inspiring  him 
to  do  so.  Let  us  see  how  he  set  about  it  and  how  he  carried  it 
through.  His  duty  consisted  in  attending  to  the  furnace  of  one  of 
those  gigantic  steam-engines  which  pumped  water  from  a  coal-pit. 
From  Dewley  he  went  to  Mid  Mill,  and  after  that  to  the  colliery  of 
Throckley-bridge,  at  which  his  wages  were  twelve  shillings  a  week. 
He  felt  he  was  getting  on.  It  was  a  proud  moment  for  him  when 
one  Saturday  evening  he  got  his  first  twelve  shillings.  "  Now,"  said 
he,  enthusiastically,  "  I  am  a  made  man  for  life." 

While  at  this  occupation  he  acquired  a  character  for  steadiness — 
that  was  a  great  point  gained.  The  world  is  always  groping  about 
for  steady  men,  and  sometimes  it  is  not  easy  getting  hold  of  them. 
George  was  rigorously  sober,  and  was  never  so  happy  as  when  he 
was  at  work,  though  it  is  also  related  of  him  that  he  took  pleasure 
after  work-hours  in  wrestling,  putting  or  throwing  the  stone,  and 
other  feats  of  muscular  skill.  He  possessed  a  powerful  frame,  and 
could  lift  heavy  weights  in  a  manner  that  was  thought  surprising. 
Rather  a  general  favorite  from  his  good-nature  and  dexterity  at 
rustic  sports,  George  likewise  gave  satisfaction  to  his  employers, 
and,  reputed  as  a  clever,  handy  young  man,  was  promoted  to  the 


j^ljj  HISTORY  OF   THE   STEAM-ENGINE. 

situation  of  engineman  or  plugman  at  Newburn.  From  looking 
after  a  furnace,  he  had  now  to  attend  to  the  working  of  a  steam- 
engine,  and  to  watch  that  the  pumps  were  kept  properly  working.  It 
was  a  post  of  responsibility,  and  not  without  trouble.  If  the  pumps 
went  wrong,  he  had  to  descend  the  pit,  and  do  his  best  to  rectify 
them  by  plugging;  that  is,  stuffing  any  hole  or  crevice  to  make 
them  draw ;  and  if  the  defect  was  beyond  his  power  of  remedy,  his 
duty  was  to  report  it  to  the  chief  engineer.  In  these  services  George 
took  immense  delight.  He  was  now  in  his  element;  could  handle, 
and  scour,  and  work  about  among  pistons,  cylinders,  wheels,  levers, 
pumps,  and  other  mechanical  contrivances,  and  regarded  the  entire 
engine  under  his  charge  with  feelings  of  keen  admiration  and  affec- 
tion. One  likes  to  hear  of  this,  for  there  is  always  something  pleas- 
ing in  the  idea  that  a  youth  is  an  enthusiast  in  the  kind  of  labor  to 
which  he  has  addressed  himself,  for  there  are  then  good  hopes  of  his 
success. 

George  was  so  fond  of  his  engine  that  he  was  never  tired  looking 
at  it,  as  it  worked  with  regularity  and  almost  with  sublimity  the 
enormous  pum;.s.  Stooping  like  a  giant,  down  went  the  great  lever 
or  pump-handle ;  a  moment's  pause  ensues,  and  then  without  an 
effort  up  is  drawn  the  prodigious  volume  of  water,  which  runs  away 
like  a  small  river.  In  the  constant  contemplation  of  this  magnifi- 
cent triumph  of  art  the  mind  of  any  one  not  lost  to  good  feeling 
cannot  fail  to  be  elevated.  At  all  events,  George  Stephenson  ex- 
perienced enviable  sensations.  Oh,  that  dear  engine,  how  he  did 
love  it !  to  him,  with  its  continuity  and  regularity  of  motion,  it  was 
like  a  living  creature.  As  a  mother  fondles  and  dresses  her  child, 
so  did  George  never  tire  fondling,  dressing  and  undressing  his  en- 
gine. It  was  not  enough  that  he  saw  the  outside  of  the  mechanism. 
It  became  a  kind  of  hobby  with  him  to  take  her — a  steam-engine  is 
her— to  pieces,  and  after  cleaning  and  examining  all  the  parts,  to  put 
her  again  into  working  order.  Then  what  joy,  when  the  steam  is 
let  on,  to  see  her  begin  to  move — to  come  to  life,  as  it  were — and  to 
commence  her  grand  pumping  operations. 

When  the  engine  was  going  in  excellent  trim,  and  nothing  was 
v^rong  with  the  pumps,  there  was  little  to  do.  The  mechanism  went 
on  of  itself  and  required  a  look  only  now  and  then.  Being  so  far 
an  easy  job  for  the  engineman,  there  was  time  to  spare.  By  way 
of  occupying  these  idle  minutes  and  hours  George  began  to  model 


HISTORY  OF  THE   STEAM-ENGINE.  xlui 

miniature  steam-engines  in  clay,  in  which  he  had  already  some  ex- 
perience. It  was  a  mere  amusement,  but  it  helped  to  fix  shapes 
and  proportions  in  his  memory.  While  so  engaged  he  was  told  of 
engines  of  a  form  and  character  he  had  never  seen.  They  were  not 
within  reach,  but  were  described  in  books.  If  he  read  these  he 
would  learn  all  about  them.  Alas !  George,  though  now  eighteen 
years  of  age,  was  still  ignorant  of  the  alphabet.  He  clearly  saw 
that  unless  he  learned  to  read  he  must  inevitably  stick  where  he  was. 
The  knowledge  of  past  times,  and  much  of  the  busy  present,  was 
shut  out  from  him.  With  these  convictions,  it  is  not  surprising  that 
our  hero  resolved  to  learn  to  read — in  fact,  to  put  himself  to  school 
and  so  remedy,  if  it  could  be  remedied,  the  neglect  on  this  score  of 
old  Bob,  his  father. 

Having  settled  in  his  own  mind  that  he  would  go  to  school,  cost 
what  it  might,  George  found  out  a  poor  teacher,  named  Robin 
Cowens,  in  the  village  of  Walbottle,  who  agreed  to  give  him  lessons 
in  the  evening  at  the  rate  of  threepence  a  week,  a  fee  which  he 
cheerfully  paid.  By  Robin  he  was  advanced  so  far  as  to  be  able  to 
write  his  own  name,  which  he  did  for  the  first  time  when  he  was 
nineteen  years  of  age.  To  improve  his  acquirements  he  afterwards, 
in  the  winter  of  1799,  went  to  an  evening  school,  kept  by  Andrew 
Robertson,  a  Scotch  dominie,  in  the  village  of  Newburn.  Here  he 
was  advanced  in  a  regular  way  to  penmanship  and  arithmetic.  But 
as  there  was  not  much  time  for  arithmetical  study  during  the  limited 
school  hours,  George  got  questions  in  figures  set  on  his  slate,  which 
next  day  he  worked  out  while  attending  the  engine.  And  that  was 
all  the  education  in  the  way  of  schooling  he  ever  got.  Very  imper- 
fect it  was  in  quality  and  extent,  but  it  admitted  him  within  the 
portals  of  knowledge,  and,  getting  that  length,  he  was  enabled  to 
pick  up  and  learn  as  he  went  on.  The  next  event  in  his  life  was  his 
removal,  in  1801,  to  the  Dolly  pit,  at  Callerton,  where  he  received 
somewhat  higher,  wages,  a  point  of  some  importance,  for  at  this 
time  the  cost  of  living  was  very  high.  Perhaps  it  was  owing  to  this 
dearth  in  food  that  George  fell  upon  the  expedient  of  devoting  his 
leisure  hours  in  the  evening  to  the  making  and  mending  of  shoes. 
Some  may  think  that  the  craft  of  shoemaking  was  quite  out  of  his 
way,  but  we  have  known  several  instances  of  shepherds  and  plough- 
men being  makers  and  menders  of  shoes  in  a  homely  style  for  their 

families,  and,  therefore,  the  "  gentle  craft "  is  not  so  very  difficult  to 
4 


xliv  HISTORY   OF   THE   STEAM-ENGINE. 

learn  as  might  be  Imagined.  George  Stephenson  became  a  toler- 
able shoemaker,  though  he  kept  chiefly  to  cobbling  or  mending.  If 
anything  could  have  spurred  him  on,  it  was  the  desire  to  sole  the 
shoes  of  his  sweetheart,  Fanny  Henderson,  and  of  these  he  is  said 
to  have  made  a  "  capital  job."  By  means  of  his  cobbling  he  was 
able  to  save  a  guinea,  which  is  recorded  as  being  the  nest-egg  of 
his  fortune.  Of  course  he  never  could  have  laid  by  so  much  as  a 
guinea  had  he,  like  most  of  his  acquaintances,  frequented  public 
houses  and  consumed  quantities  of  beer.  But  no  one  ever  saw  him 
the  worse  for  drink,  and  while  others  were  soaking  in  taverns,  or 
amusing  themselves  with  cock-fighting  and  dog-fighting,  he  was  at 
home,  either  trying  to  increase  his  sum  of  knowledge  or  applying 
.  himself  to  some  useful  occupation  which  was  in  itself  an  amuse- 
ment. His  sobriety  and  industry  had  their  reward.  He  was  en- 
abled to  furnish  a  house  decently  and  to  marry  Fanny  Henderson. 
The  marriage  was  celebrated  on  November  28,  1802,  and  the  pair 
betook  themselves  to  the  neat  home  that  had  been  prepared  at 
Willington  Ballast  Quay,  a  place  on  the  Tyne,  about  six  miles  from 
.Newcastle. 

Settling  down  as  a  married  man,  George  continued  to  devote 
leisure  hours  to  study  or  to  some  handicraft  employment.  From 
•making  and  mending  shoes,  he  proceeded  to  mend  clocks  and  be- 
came known  among  his  neighbors  as  a  wonderfully  clever  clock- 
doctor.  It  is  said  that  he  was  led  into  this  kind  of  employment  by 
an  accident.  His  chimney  having  gone  on  fire,  the  neighbors  in 
putting.it  out  deluged  the  house  with  water  and  damaged  the  eight- 
day  clock.  Handy  at  machinery,  and  wishing  to  save  money,  George 
■determined  to  set  the  clock  to  rights.  He  took  it  to  pieces,  cleaned 
it,  reorganized  it  and  made  it  go  as  well  as  ever.  There  was  a  tri- 
umph !  After  this  he  was  often  employed  as  a  repairer  of  clocks, 
by  which  he  added  a  little  to  his  income.  On  December  16,  1803, 
was  born  his  only  son  Robert,  who  lived  to  be  at  the  head  of  the 
railway  engineering  profession.  But  before  either  George  or  his 
son  could  arrive  at  distinction,  there  was  not  a  little  to  be  done.  As 
a  brakeman  George  had  charge  of  the  coal-lifting  machinery  at 
Willington,  and  subsequently  at  Killingworth,  and  in  this  depart- 
ment, as  well  as  engineman,  he  gradually  but  surely  gained  the 
reputation  of  being  an  ingenious  and  trustworthy  workman.  At 
Killingworth,  which  is  .about  .s.even  miles  north  of  Newcastle,  he 


HISTORY   OF   THE   STEAM-ENGINE.  xlv 

suffered  the  great  misfortune  of  losing  his  wife.  This  sad  blow  fell 
upon  him  in  1804,  with  his  son  still  an  infant. 

The  next  thing  we  hear  of  him  is  that,  leaving  his  child  in  charge 
of  a  neighbor,  he  went  by  invitation  to  superintend  an  engine  at 
some  works  near  Montrose,  in  Scotland,  which  journey,  about  a 
hundred  and  fifty  miles,  he  performed  on  foot.  Disagreeing  after  a 
short  period  with  the  owners,  he  trudged  back  to  his  home  at  Kil- 
lingworth,  bringing  with  him  £28  as  savings.  One  of  the  first 
things  he  did  after  his  return  was  to  succor  his  father,  now  an  aged 
and  blind  man,  whom,  with  his  old  mother,  he  placed  in  a  comfort- 
able cottage  in  his  own  neighborhood.  Again  he  followed  the  em- 
ployment of  brakesman  at  West  Moor  pit,  and  was  continuing  to 
save,  when,  in  1807,  his  small  accumulations  were  in  a  moment 
wholly  swept  away.  He  was  drawn  for  the  militia,  and  every  shil- 
ling he  had  saved  was  paid  away  for  a  substitute.  To  be  thrust 
back  into  poverty  in  so  hateful  a  manner  almost  upset  his  philoso- 
phy, and  he  strongly  meditated  emigrating  to  America.  Fortu- 
nately for  England,  his  spirits  revived,  and  he  held  on  his  course.  In 
addressing  a  society  of  young  operatives  many  years  afterwards,  he  re- 
ferred as  follows  to  this  dark  period  in  his  Itfe  :  "  Well  do  I  remember 
ihe  beginning  of  my  career  as  an  engineer,  and  the  great  perseverance 
that  was  required  of  me  to  get  on.  Not  having  served  an  appren- 
ticeship, I  had  made  up  my  mind  to  go  to  America,  considering  that 
no  one  in  England  would  trust  me  to  act  as  engineer.  However,  I 
was  trusted  in  some  small  matters,  and  succeeded  in  giving  satisfac- 
tion. Greater  trusts  were  reposed  in  me,  in  which  I  also  succeeded. 
Soon  after,  I  commenced  making  the  locomotive  engine ;  and  the 
results  of  my  perseverance  you  have  this  day  witnessed." 

It  says  much  for  Stephenson,  that  under  pinching  difficulties  he 
did  not  only  take  care  of  his  old  parents,  but  gave  his  child  as  good 
an  education  as  was  in  his  power.  The  want  of  learning  he  had 
himself  acutely  felt,  and  this  deficiency,  if  at  all  practicable,  he  wished 
to  avert  from  his  son.  In  one  of  his  public  speeches  late  in  life,  he 
observed :  "  In  the  earlier  period  of  my  career,  when  Robert  was  a 
little  boy,  I  saw  how  deficient  I  was  in  education,  and  I  made  up  my 
mind  that  he  should  not  labor  under  the  same  defect,  but  that  I 
would  put  him  to  a  good  school,  and  give  him  a  liberal  training.  I 
was,  however,  a  poor  man ;  and  how  do  you  think  I  managed  ?  I 
betook  myself  to  mending  my  neighbors'  clocks   and   watches  at 


xlvi  HISTORY   OF   THE   STEAM-ENGINE. 

nights,  after  my  daily  labor  was  done,  and  thus  I  procured  the  means 
of  educating  my  son." 

In  i8iO,  an  opportunity  occurred  for  George  Stephenson  signaliz- 
ing himself  A  badly-constructed  steam-engine  at  Killingworth 
High  pit  could  not  do  its  work ;  one  engineer  after  another  tried  to 
set  it  to  rights,  but  all  failed ;  and  at  last  in  despair  they  were  glad 
to  let  "  Geordie"  try  his  hand,  though  with  his  reputation  for  clever- 
ness they  did  not  expect  him  to  succeed.  To  their  mortification  and 
astonishment,  he  was  perfectly  successful.  He  took  the  engine  to 
pieces,  rearranged  it  skilfully,  and  set  it  to  work  in  the  most  effectual 
manner.  Besides  receiving  a  present  of  £iO  for  this  useful  service, 
he  was  placed  on  the  footing  of  a  regular  engineer,  and  afterwards 
consulted  in  cases  of  defective  pumping  apparatus. 

Although  thus  rising  in  public  estimation,  he  still  knew  his  defi- 
ciencies, and  strove  to  improve  by  renewed  evening  studies.  One 
of  his  acquaintances,  named  John  Wigham,  gave  him  some  useful 
instructions  in  branches  of  arithmetic,  of  which  he  had  an  imperfect 
knowledge,  and  the  two  together,  with  the  aid  of  books,  spent  many 
pleasant  evenings  in  getting  an  insight  into  chemistry  and  other 
departments  of  practical  seiefice.  His  steadiness  was  at  times  sorely 
tried  by  the  solicitations  of  neighbors  in  his  own  rank  "  to  come 
and  take  a  glass  o'  yill  ; "  but  resolutions  to  be  temperate  and  to 
save  for  the  sake  of  Robert's  education,  enabled  him  to  withstand 
tempters  of  all  kinds.  By  dint  of  such  reserve,  he  was  able  to  save 
a  hundred  guineas,  which,  in  consequence  of  the  demand  for  bullion 
during  the  French  war,  he  sold  to  money-brokers  for  twenty-six 
shillings  each.  At  intervals  in  his  ordinary  labor,  he  employed 
himself  in  building  an  oven  and  some  additional  rooms  to  his  cot- 
tage, which  he  likewise  rendered  attractive  by  a  garden  cultured 
with  his  own  hands. 

The  year  i8i2  marked  Stephenson's  rise  to  the  position  of  a 
colliery  engineer  and  planner  of  machinery  for  working  pits  and 
wheeling  off  coal.  Proprietors  and  managers  began  to  entertain  a 
high  idea  of  his  qualities,  which  were  obviously  not  those  of  a  pre- 
tender. Referring  to  this  period,  when  in  1835  he  gave  evidence 
before  a  select  committee  of  the  House  of  Commons  on  accidents 
in  mines,  he  said:  "After  making  some  improvements  in  the  steam- 
engines  above  ground,  I  was  then  requested  by  the  manager  of  the 
colliery  to  go  underground  along  with  him  to  see  if  any  improve- 


HISTORY   OF   THE   STEAM-ENGINE.  xlvil 

ments  could  be  made  in  the  mines,  by  employing  machinery  as  a 
substitute  for  manual  labor  and  horse-power  in  bringing  the  coals 
out  of  the  deeper  workings  of  the  mine.  On  my  first  going  down 
the  Killingworth  pit,  there  was  a  steam-engine  underground  for  the 
purpose  of  drawing  water  from  a  pit  that  was  sunk  at  some  distance 
from  the  first  shaft.  The  Killingworth  coal-field  is  considerably  dis- 
located. After  the  colliery  was  opened,  at  a  very  short  distance  from 
the  shaft,  they  met  with  one  of  those  dislocations,  or  dikes,  as  they 
are  called.  The  coal  was  thrown  down  about  forty  yards  (or 
abruptly  lay  at  that  much  lower  level).  Considerable  time  was 
spent  in  sinking  another  pit  to  this  depth.  And  on  my  going  down 
to  examine  the  work,  I  proposed  making  the  engine,  which  had 
been  erected  some  time  previously,  to  draw  the  coals  up  an  inclined 
plane,  which  descended  immediately  from  the  place  where  it  was 
fixed.  A  considerable  change  was  accordingly  made  in  the  mode 
of  working  the  colliery,  not  only  in  applying  the  machinery,  but 
employing  putters  instead  of  horses  in  bringing  the  coals  from  the 
hewers;  and  by  those  changes  the  number  of  horses  in  the  pit  was 
reduced  from  one  hundred  to  fifteen  or  sixteen.  During  the  time  I 
was  engaged  in  making  these  important  alterations,  I  went  round 
the  workings  in  the  pit  with  the  viewer  almost  every  time  that  he 
went  into  the  mine — not  only  at  Killingworth,  but  at  Mountmoor, 
Derwentcrook,  Southmoor,  all  which  collieries  belonged  to  Lord 
Ravensworth  and  his  partners;  and  the  whole  of  the  machinery  in 
all  these  collieries  was  put  under  my  charge." 

Leaving  George  engaged  in  these  useful  pursuits,  which  were 
intermingled  with  scientific  studies  with  his  son,  when  he  came 
home  from  school  at  Newcastle,  we  may  take  a  glance  at  the  begin- 
nings of  railways  and  locomotives.  It  is  certain  there  were  railways 
of  a  rude  kind  in  England  as  early  as  the  commencement  of  the 
eighteenth  century.  The  rails  were  at  first  of  wood,  then  the  wood 
was  shod  with  slips  of  iron,  and  lastly,  they  were  altogether  rods  or 
bars  of  iron.  These  old  railways,  which  were  better  known  by  the 
name  of  tramways,  were  devised  for  the  transit  of  coals  from  pits, 
the  carriages  being  deep  wooden  wagons  pulled  by  horses. 
Strangely  enough,  there  was  a  railway  of  this  kind  across  the 
fields  from  the  coal-pits  of  Tranent  to  the  small  seaport  Cockenzie, 
when  the  battle  of  Prestonpans  was  fought  on  the  ground  in  1745 — 
which  line  of  rails,  honored  by  having  been  the  site  of  Cope's  can- 


xlviii 


HISTORY   OF   THE   STEAM-ENGINE. 


non,  Still  exists.  Wherever  there  were  coal  or  iron  mines,  these 
tramways  were  introduced;  nor  could  they  fail  to  get  into  use,  for  a 
single  horse  could  draw  upon  them  a  load  that  would  have  required 
twenty  horses  on  a  common  highway. 


CUGNOTS    ENGINE,    1 7/0 


To  Nicholas  Joseph  Cugnot,  an  officer  of  engineers  in  the  French 
army,  born  1725,  is  due  the  honor  of  the  first  successful  application 
of  steam  to  locomotion ;  it  was  designed  for  common  roads  and  was 
in  1770  run  at  the  rate  of  about  four  miles  an  hour  in  the  neighbor- 
hood of  Versailles,  in  the  presence  of  a  multitude  of  scientific  and 
curious  spectators. 


trevethick's  steam-carriage,  1803. 

The  credit  of  inventing  a  carriage  moved  by  steam  in  England  is  due 
to  Richard  Trevethick,  a  Cornish  tin-miner,  and  a  clever  but  some- 
what eccentric  person.  He  made  a  steam-carriage  to  run  on  common 
roads  or  rails  in  1802,  and  exhibited  it  in  the  metropolis.     Improv- 


HISTORY   OF   THE   STEAM-ENGINE. 


xlix 


incr  on  this,  he,  in  1804,  completed  a  locomotive  to  draw  coal  on 
the  Merthyr-Tydvil  Railway  in  South  Wales.  It  did  its  work  well, 
drawing  wagons  with  ten  tons  of  iron  at  the  rate  of  five  miles  an 


BLENKINSOP'S   TOOTH-WHEELED    LOCOMOTIVE,    181I. 

hour;  but  it  was  an  ill-constructed  machine,  and  having  gone  out 
of  order,  it  was  deserted  by  its  inventor,  and  no  more  was  heard  of 
locomotives  for  some  years.  Next  came  the  invention  of  Mr. 
Blenkinsop,  who  planned  a  locomotive  for  coal  traction,  which  was 


\^)  If/ 


I^=l!=^?l- 


BRUNTON's    STILT    LOCOMOTIVE,    1813. 

used  on  a  railway  from  Middleton  Collieries  to  Leeds,  and  could 
haul  as  many  as  thirty  loaded  wagons  at  a  speed  of  three  and  a 
quarter  miles  an  hour.  What  long  kept  the  invention  in  this  back- 
ward state  was  the  erroneous  notion,  that  unless  the  locomotive  had 


1 


HISTORY   OF  THE   STEAM-ENGINE. 


wheels  with  cogs  to  pull  against  cogs  in  the  railway,  it  would  slip, 
and  not  get  forward;  and  it  was  not  until  this  fanciful  idea  was  got 
rid  of  that  much  good  was  done  with  locomotive  power.  We  lind 
on  record  the  description  of  a  steam-engine  moved  by  stilts  or 
crutches  which  alternately  pressed  upon  and  lifted  from  the  ground 
like  the  legs  of  a  horse;  this  machinre  was  patented  and  exhibited 
in  1 813. 

Finally,  in  181 3,  Mr.  Blackett,  an  engineer  better  advised  than 
his  predecessors,  demonstrated  that  the  enormous  weight  of 
the  adhesion  between  the  smooth  rails   and  the  equally  smooth 


Stephenson's  locomotive,  18 15. 


wheels  would  always  suffice  to  prevent  the  wheels  from  slipping, 
and  he  established  his  theory  by  easy  experiments.  We  may  con- 
ceive that  for  about  twenty  years  subsequent  to  18 13,  there  were 
many  geniuses  at  work  contriving  improved  locomotives,  and  among 
these  none  thought  more  diligently  or  deeply  than  George  Stephen- 
son. After  a  variety  of  experiments,  he  was  satisfied  with  Blackett's 
theory  that  there  would  be  sufficient  adhesion  in  the  wheels  to  over- 
come any  tendency  to  shp;  teeth  or  cogs  were  accordingly  dismissed. 
In  July,  1 8 14,  he  was  able  to  begin  running  his  locomotive,  called  the 
Bhicher,  on  the  Killingworth  Railway.  It  was  still  only  a  coal-drag, 
and  at  best  a  clumsy  apparatus,  but  it  hauled  eight  loaded  wagons 


HISTORY   OF   THE   STEAM-ENGINE.  \{ 

weighing  thirty  tons,  at  about  four  miles  an  hour.  This  was  un- 
doubtedly a  success;  the  thing  could  be  done;  yet,  as  the  cost  of 
working  was  about  as  great  as  that  by  horses,  little  was  gained. 
There  must  be  fresh  trials.  As  by  a  flash  of  inspiration,  Stephen- 
son saw  the  leading  defect  and  the  method  for  curing  it.  The  fur- 
nace wanted  draught,  which  he  gave  by  sending  the  waste  steam 
into  the  chimney;  and  at  once,  by  increased  evolution  of  steam,  the 
power  of  the  engine  was  doubled  or  tripled.  In  1815  he  had  a  new 
locomotive  at  work,  combining  this  and  some  minor  improvements. 
Still,  there  was  much  to  be  done  to  perfect  the  machine.  The  cost 
of  working  was  so  considerable,  that  locomotive  power  did  not  meet 
with  general  approval ;  the  fact  was,  that  railways  at  this  period  were 
not  so  accurately  finished  as  they  now  are,  and  smooth  and  easy 
running  ought  not  to  have  been  expected.  It  was  only  step  by  step 
that  both  rails  and  moving  apparatus  were  brought  to  a  compara- 
tively perfect  state. 

At  the  Killingworth  Colliery,  Stephenson  continued  to  plan  his 
improvements,  and  also  to  advance  in  general  knowledge  in  the 
society  of  his  son,  who,  on  leaving  school  in  18 18,  was  placed  as  an 
apprentice  to  learn  practically,  underground,  the  business  of  a 
viewer  of  coal-mines;  and  in  1820  he  went  for  a  session  of  six 
months  to  the  University  of  Edinburgh.  The  cost  of  this  piece  of 
education  was  £80,  which  the  father  could  not  well  spare  ;  but  the 
prize  for  skill  in  mathematics  which  his  son  brought  home  with  him 
at  the  end  of  the  session  was  thought  to  be  ample  repayment. 
Acquiring  a  knowledge  of  railways,  Robert  was  appointed  to  pro- 
ceed to  Colombia,  South  America,  to  superintend  some  railway 
operations.  One  day,  previous  to  setting  out,  he  dined  with  his 
father,  and  a  young  man  named  Dixon  was  of  the  party.  An  anec- 
dote is  related  to  show  the  strong  faith  which  George  Stephenson 
at  this  time  entertained  regarding  railway  progress.  "  Now,  lads," 
said  he  to  the  two  young  men  after  dinner,  "  I  will  tell  you  that  I 
think  you  will  live  to  see  the  day,  though  I  may  not  live  so  long, 
when  railways  will  come  to  supersede  almost  all  other  methods  of 
conveyance  in  this  country — when  mail-coaches  will  go  by  railway, 
and  railways  will  become  the  great  highway  for  the  king  and  all  his 
subjects.  The  time  is  coming  when  it  will  be  cheaper  for  a  work- 
ingman  to  travel  on  a  railway  than  to  walk  on  foot.  I  know  there 
are  great  and  almost  insurmountable  difficulties  that  will  have  to  be 


IJJ  HISTORY   OF   THE    STEAM-ENGINE. 

encountered ;  but  what  I  have  said  will  come  to  pass  as  sure  as  we  live. 
I  only  wish  I  may  live  to  see  the  day,  though  that  I  can  scarcely 
hope  for,  as  I  know  how  slow  all  human  progress  is,  and  with  what 
difficulty  I  have  been  able  to  get  the  locomotive  adopted,  notwith- 
standing my  more  than  ten  years'  successful  experiment  at  Killing- 
worth." 

Stephenson's  attention  had  frequently  been  drawn  to  the  deplora- 
ble destruction  of  life  in  coal-mines  by  the  explosion  of  inflammable 
air  or  fire-damp.  As  early  as  1815  he  devised  a  safety-lamp  to 
guard  against  those  accidents.  As  it  was  about  the  same  period 
that  Dr.  Clanny  and  Sir  Humphry  Davy  invented  their  respective 
safety-lamps  for  the  like  purpose,  it  is  not  quite  clear  to  whom  the 
merit  of  the  discovery  should  be  assigned — though  Stephenson's 
claim  has  been  strongly  insisted  on.  As  this  is  not  the  proper  place 
for  debating  the  point,  and,  besides,  as  the  matter  is  of  inferior 
importance,  we  pass  on  to  what  is  of  real  moment — Stephenson's 
perfecting  of  the  locomotive;  for  on  that  his  fame  properly  rests. 
Pursuing  schemes  of  this  kind,  after  parting  with  his  son,  his 
advancement  was  in  no  small  degree  owing  to  certain  services  in 
which  he  was  engaged  on  the  Stockton  and  Darlington  Railway,  a 
concern  greatly  promoted  by  Mr.  Edward  Pease,  a  man  of  property 
and  intelligence  in  the  district.  The  engineering  of  this  railway  was 
given  up  to  Stephenson,  and  in  some  respects  it  became  a  model  for 
railway  works — the  gauge  of  four  feet  eight  and  a  half  inches,  which 
is  now  usually  followed,  having  here  been  adopted  in  a  regular 
manner  in  imitation  of  the  old  tramways.  Already  a  manufactory 
of  engines  had  been  set  up  at  Newcastle,  in  which  George  Stephen- 
son was  a  partner,  and  from  this  establishment  three  locomotives 
were  ordered  by  the  directors  of  the  Stockton  and  Darlington  Rail- 
way Company;  for  in  their  act  of  Parliament  they  had  taken  power 
to  employ  steam  in  the  traction  of  goods  and  passengers.  The 
opening  of  this  the  first  public  railway  took  place  on  27th  Septem- 
ber, 1825,  in  presence  of  an  immense  concourse  of  spectators.  A 
local  newspaper  records  the  event  as  follows:  "The  signal  being 
given,  the  engine  started  off  with  this  immense  train  of  carriages, 
and  such  was  its  velocity,  that  in  some  parts  the  speed  was  fre- 
quently twelve  miles  an  hour;  and  at  that  time  the  number  of  pas- 
sengers was  counted  to  be  450,  which,  together  with  the  coals,  mer- 
chandise, and  carriages,  would  amount  to  near  ninety  tons.     The 


HISTORY   OF   THE   STEAM-ENGINE.  \[[[ 

engine,  with  its  load,  arrived  at  Darlington,  a  distance  of  eight  and 
three-quarter  miles,  in  sixty-five  minutes.  The  six  wagons  loaded 
with  coals,  intended  for  Darlington,  were  then  left  behind;  and 
obtaining  a  fresh  supply  of  water,  and  arranging  the  procession  to 
accommodate  a  band  of  music  and  numerous  passengers  from  Dar- 
lington, the  engine  set  off  again,  and  arrived  at  Stockton  in  three 
hours  and  seven  minutes,  including  stoppages,  the  distance  being 
nearly  twelve  miles."  The  drawing  of  about  600  passengers,  as 
there  appear  to  have  been  in  the  train,  at  the  rate  of  four  miles  an 
hour,  was  thought  very  marvellous.  A  month  later  a  regular  pas- 
senger-coach, called  the  Experiment,  was  placed  on  the  line;  it  was 
drawn  by  a  horse  in  two  hours.  The  haulage  of  coal  only  was 
effected  by  the  locomotive.  It  was  evident  that  the  making  of 
engines  was  still  in  its  infancy.  Stephenson,  at  his  manufactory, 
continued  to  carry  out  improvements,  in  which  he  was  assisted  by 
his  son,  on  his  return  from  South  America  in  1827. 

When  the  project  of  the  Manchester  and  Liverpool  Railway  was 
before  Parliament  in  1825,  George  Stephenson,  in  the  face  of  no 
little  browbeating  from  ignorant  and  interested  opponents,  gave 
good  evidence  respecting  the  practicability  and  safety  of  drawing 
passenger-trains  with  locomotives,  though  still  speaking  diffidently 
as  to  a  speed  of  more  than  from  fifteen  to  twenty  miles  an  hour. 
Few  things  are  more  amusing  than  the  real  or  affected  incredulity 
of  members  of  the  legislature  at  this  time  as  to  railway  transit,  not- 
withstanding that  the  propulsion  of  coal-trains  by  locomotive  power 
had  been  satisfactorily  demonstrated.  It  is  always,  however,  easy  to 
find  fault  and  to  disbelieve;  and  the  opposition  which  railways  at 
first  encountered  is  no  way  singular.  Stephenson's  assertion  during 
his  examination  before  a  committee  of  the  House,  that  it  would  not 
be  difficult  to  make  a  locomotive  travel  fifteen  or  twenty  miles  an 
hour,  provoked  one  of  the  members  to  reply  that  the  engineer  could 
only  be  fit  for  a  lunatic  asylum.* 

Parliamentary  sanction  once  obtained,  the  Liverpool  and  Man- 
chester Railway  Company  set  to  work  upon  their  novel  and  im- 
portant undertaking — novel,  inasmuch  as  its  scheme  and  magnitude 

*  It.  was  on  this  occasion  that  Stephenson  was  asked  by  a  member  of  the  Parliamentary 
Committee,  "  Mr.  Stephenson,  what  would  happen  if  a  cow  got  on  the  track,  with  your 
engine  running  at  fifteen  miles  an  hour?  "  To  this  Stephenson  replied,  "  It  would  be 
awkward  for  the  coo." 


\[y  HISTORY   OF   THE   STEAM-ENGINE. 

exceeded  all  that  had  been  previously  attempted  of  a  similar  nature. 
Stephenson,  who  had  already  won  a  reputation,  was  appointed 
engineer,  at  i^iooo  a  year,  and  a  chief  point  determined  on  was, 
that  the  line  should  be  as  nearly  as  possible  straight  between  the 
two  towns.  In  the  carrying  out  of  this  design  the  series  of  "  engi- 
neering difficulties"  was  first  encountered,  the  overcoming  of  which 
has  called  forth  an  amount  of  scientific  knowledge,  of  invention, 
ingenuity,  and  mechanical  hardihood  unprecedented  in  the  history 
of  human  labor.  Hills  were  to  be  pierced  or  cut  through,  embank- 
ments raised,  viaducts  built,  and  four  miles  of  watery  and  spongy 
bog,  called  Chat  Moss,  converted  into  a  hardened  road — all  which 
was  successfully  effected. 

The  line  being  at  length  completed,  the  directors  offered  a  prize 
of  i^500  for  the  best  locomotive  that  could  be  brought  forward  to 
compete  in  running  on  a  certain  day.  It  was  stipulated  that  the 
engine  should  consume  its  own  smoke;  be  not  more  than  six  tons 
in  weight;  and  be  able  to  draw  twenty  tons,  including  tender  and 
water-tank,  at  ten  miles  an  hour;  be  supported  on  springs,  and  rest 
on  six  wheels;  must  have  two  safety-valves;  the  pressure  of  steam 
should  not  exceed  fifty  pounds  to  the  square  inch;  and  the  price  of 
the  engine  was  not  to  be  above  ;^55o.  Stephenson  determined  to 
compete,  and  built  an  engine  called  the  Rocket  for  the  purpose. 
The  day  of  trial  was  the  8th  of  October,  1829,  when  three  engines 
were  brought  forward.  Stephenson  was  there  with  his  Rocket, 
Hackworth  with  the  Sanspareil,  and  Braithwaite  and  Ericcson  with 
the  Novelty.  The  test  assigned  was  to  run  a  distance  of  thirty  miles 
at  not  less  than  ten  miles  an  hour,  backwards  and  forwards  along  a 
two-mile  level  near  Rainhill,  with  a  load  three  times  the  weight  of 
the  engine.  The  Novelty,  after  running  twice  along  the  level,  was 
disabled  by  failure  of  the  boiler-plates,  and  withdrawn.  The  Sans- 
pareil traversed  eight  times  at  a  speed  of  nearly  fifteen  miles  an 
hour,  when  it  was  stopped  by  derangement  of  the  machinery.  The 
Rocket  was  the  only  one  to  stand  the  test  and  satisfy  the  conditions. 
This  engine  travelled  over  the  stipulated  thirty  miles  in  two  hours 
and  seven  minutes  nearly,  with  a  speed  at  times  of  twenty-nine 
miles  an  hour,  and  at  the  slowest  nearly  twelve;  in  the  latter  case 
exceeding  the  advertised  maximum;  in  the  former,  tripling  it. 
Here  was  a  result!  An  achievement  so  surprising,  so  unexpected, 
as  to  be  almost  incredible.  Was  it  not  a  delusion? — had  it  been 
really  accomplished  ? — and  could  it  be  done  again  ? 


HISTORY   OF   THE   STEAM-ENGINE. 


Iv 


The  prize  of  ^500  was  at  once  awarded  to  the  makers  of  the 
Rocket.  Their  engine  was  not  only  remarkable  for  its  speed,  but 
also  for  the  contrivances  by  which  that  speed  was  attained.  Most 
important  among  them  was  the  introduction  of  tubes  passing  from 
end  to  end  of  the  boiler,  by  means  of  which  so  great  an  additional 
surface  was  exposed  to  the  radiant  heat  of  the  fire,  that  steam  was 
generated  much  more  rapidly,  and  a  higher  temperature  maintained 
at  a  smaller  expenditure  of  fuel  than  usual.  The  tubular  boiler  was 
indeed  the  grand  fact  of  the  experiment.  Without  tubes,  steam 
could  never  have  been  produced  with  the  rapidity  and  heat  essential 


Stephenson's  locomotive  engine,  the  "rocket,"  1829.* 

to  quick  locomotion.  In  more  senses  than  one,  the  trial  of  the 
three  locomotives  in  October,  1829,  marks  an  epoch.  By  burning 
coke  instead  of  coal  the  stipulated  suppression  of  smoke  was 
effected;  the  quantity  consumed  by  the  Rocket  during  the  experi- 
ment was  half  a  ton.  The  coke  and  water  were  carried  in  a  tender 
attached  to  the  engine. 

On  the  15th  of  September,  1830,  the  railway  was  opened.     The 


*  A,  the  boiler,  6  feet  long,  3  feet  4  inches  in  diameter.  B,the  fire-box  enclosed  in  a 
casing  3  inches  wide,  containing  water.  C,  a  water  pipe  communicating  between  the 
casing  and  the  boiler.  D,  a  steam-pipe  between  the  same.  E,  two  pipes  ^one  from 
each  cylinder)  for  throwing  the  exhaust  steam  into  the  chimney. 


|yj         ^  HISTORY   OF   THE   STEAM-ENGINE 

two  great  towns,  with  due  regard  to  the  importance  of  the  event, 
made  preparations  for  it  with  a  spirit  and  Hberality  worthy  of  their 
wealth  and  enterprise.  Members  of  the  government,  and  distin- 
guished individuals  from  various  quarters,  were  invited  to  be  present 
at  the  opening.  On  the  memorable  day  a  train  was  formed  of  eight 
locomotives  and  twenty-eight  carriages,  in  which  were  seated  the 
eminent  visitors  and  other  persons  present  on  the  occasion,  to  the 
number  of  6oo.  The  NortJmnibrian,  one  of  the  most  powerful  of 
the  engines,  took  the  lead,  followed  by  the  train,  which,  as  it  rolled 
proudly  onwards,  impressed  all  beholders  with  a  grand  idea  of  the 
energies  of  art,  and  of  the  power  destined  soon  afterwards  to  effect 
the  greatest  of  civil  revolutions.  At  Parkfield,  seventeen  miles  from 
Manchester,  a  halt  was  made  to  replenish  the  water-tanks,  when  the 
accident  occurred  by  which  Mr.  Huskisson  lost  his  life,  and  tem- 
pered the  triumph  by  a  general  sentiment  of  regret.  The  proceed- 
ings, however,  though  subdued,  were  carried  out  in  accordance  with 
the  arrangements  prescribed. 

Business  began  the  next  day.  The  Northtnnbrian  drew  a  train 
with  130  passengers  from  Liverpool  to  Manchester  in  one  hour  and 
fifty  minutes;  and  before  the  close  of  the  week  six  trains  daily  were 
regularly  running  on  the  line.  The  surprise  and  excitement  already 
created  were  further  increased  when  one  of  the  locomotives  by  itself 
travelled  the  thirty-one  miles  in  less  than  an  hour.  Of  the-  thirty 
stage-coaches  which  had  plied  between  the  two  towns,  all  but  one 
went  off  the  road  very  soon  after  the  opening,  and  their  500  passen- 
gers multiplied  at  once  into  1600.  In  December  commenced  the 
transport  of  goods  and  merchandise,  and  afforded  further  cause  of 
astonishment ;  for  a  loaded  train,  weighing  eighty  tons,  was  drawn 
by  the  Planet  engine  at  from  twelve  to  sixteen  miles  an  hour.  In 
February,  1 831,  the  Samson  accomplished  a  greater  feat,  having 
conveyed  164^  tons  from  Liverpool  to  Manchester  in  two  hours 
and  a  half,  including  stoppages — as  much  work  as  could  have  been 
performed  by  seventy  horses. 

There  are  some  who  will  remember  the  wonder  and  excitement 
created  by  these  results  in  all  parts  of  the  kingdom.  The  facts 
could  not  be  disputed.  Neither  the  laws  of  nature  nor  science 
could  be  brought  to  accord  with  the  views  of  those  who  saw  in  the 
new  agencies  the  elements  of  downfall  and  decay.  Even  the  com- 
pany had  gone  surprisingly  astray  in  their  calculations.     Believing 


HISTORY   OF   THE    STEAM-ENGINE.  Ivii 

that  the  greater  part  of  their  business  and  of  their  revenue  would 
be  derived  from  the  transport  of  heavy  goods,  they  had  set  down 
;^20,000  a  year  only  as  the  estimated  return  from  passenger  traffic ; 
and  scarcely  a  week  had  passed  before  they  became  aware  of  the 
fact,  as  agreeable  as  it  was  unexpected,  that  passengers  brought  the 
greatest  return.  The  whole  number  conveyed  from  the  time  of 
opening  to  the  end  of  the  year — three  months  and  a  half — was  more 
than  71,000.  This  line,  as  is  well  known,  now  forms  part  of  that 
vast  system,  the  London  and  Northwestern  Railway. 

These  successes  placed  George  Stephenson  in  an  eminent  position 
in  the  engineering  world.  He  was  sought  after  for  various  under- 
takings ;  the  business  with  which  he  was  connected  at  Newcastle 
increased;  and,  in  short,  he  was,  as  far  as  worldly  consideration  and 
circumstances  are  concerned,  a  "  made  man."  His  steadiness,  per- 
severance, and  skill  had  been  acknowledged  and  rewarded.  He 
and  his  son  further  perfected  the  locomotive,  which  he  lived  to  see 
running  at  upwards  of  forty  miles  an  hour.  In  1837,  he  removed 
to  Tapton  Hall,  a  residence  near  Chesterfield,  and  in  1840,  he  inti- 
mated his  design  of  retiring  from  his  more  active  professional  pur- 
suits. He,  however,  did  not  subside  into  idleness  or  indifference ; 
but  gave  time  to  various  railway  matters,  and  took  pleasure  in 
attending  public  meetings  of  mechanics'  institutes.  It  was  a  great 
day  for  him,  the  i8th  of  June,  1844,  when  the  first  train  came  with- 
out break  from  London  to  Newcastle  in  the  space  of  nine  hours. 
At  the  festival  on  that  day  at  Newcastle,  to  signalize  the  event,  all 
eyes  were  turned  on  old  George  Stephenson,  when,  in  reply  to  a 
complimentary  speech  of  Mr.  Liddell,  M.  P.,  he  gave  the  following 
brief  but  interesting  account  of  his  career. 

"As  the  honorable  member  has  referred  to  the  engineering  efforts 
of  my  early  days,  it  may  not  be  amiss  if  I  say  a  few  words  to  you 
on  that  subject,  more  especially  for  the  encouragement  of  my 
younger  friends.  Mr.  Liddell  has  told  you  that  in  my  early  days  I 
worked  at  an  engine  on  a  coal-pit.  I  had  then  to  work  early  and 
late,  and  my  employment  was  a  most  laborious  one.  For  about 
twenty  years  I  had  often  to  rise  to  my  labor  at  one  and  two  o'clock 
in  the  morning,  and  worked  until  late  at  night.  Time  rolled  on, 
and  I  had  the  happiness  to  make  some  improvements  in  engine- 
work.  The  company  will  be  gratified  when  I  tell  them  that  the  first 
locomotive  that  I  made  was  at  Killingworth  Colliery.     The  owners 


\y[[[  HISTORY   OF   THE   STEAM-ENGINE. 

were  pleased  with  what  I  had  done  in  the  coUieries ;  and  I  then 

proposed  to  make  an  engine  to  work  upon  the  smooth  rails.    It  was 

with  Lord  Ravensworth's  money  that  my  first  locomotive  was  built. 

Yes,  Lord  Ravensworth  and  his  partners  were  the  first  gentlemen 

to  intrust  me  with  money  to  make  a  locomotive.     That  was  more 

than  thirty  years  ago ;   and  we  first  called  it  *  My  Lord.'     I  then 

stated  to  some  of  my  fi"iends,  now  living,  that  those  high  velocities 

with   which   we   are   now  so   familiar  would,   sooner    or  later,    be 

attained,  and  that  there  was  no  limit  to  the  speed  of  such  an  engine, 

provided  the  works   could  be   made   to  stand ;   but  nobody  would 

believe  me  at  that  time.     The  engines  could  not  perform  the  high 

velocities  now  reached,  when  they  were  first  invented;  but,  by  their 

superior  construction,  an   immense  speed  is  now  capable  of  being 

obtained.     In  what  has  been  done  under  my  management,  the  merit 

is   only  in  part   my   own.     Throughout,   I   have  been   most   ably 

seconded  and  assisted  by  my  son.    In  the  early  period  of  my  career, 

and  when  he  was  a  little  boy,  I  felt  how  deficient  I  was  in  education, 

and  made  up  my  mind  that  I  would  put  him  to  a  good  school.     I 

determined    that  he  should    have  as  liberal  a  training  as  I  could 

afford  to  give  him.     I  was,  however,  a  poor  man ;  and  how  do  you 

think  I  managed  ?      I   betook   myself  to   mending  my  neighbors' 

clocks  and  watches  at  night,  after  my  daily  labor  was  done.     By 

this  means  I  saved  money,  which  I  put  by ;  and,  in  course  of  time, 

I  was  thus  enabled  to  give  my  son  a  good  education.     While  quite 

a  boy  he  assisted  me,  and  became  a  companion  to  me.     He  got  an 

appointment  as  under-viewer  at  Killingworth  ;  and  at  nights,  when 

we  came  home,  we  worked  together  at  our  engineering.    I  got  leave 

from  my  employers  to  go  from  Killingworth  to  lay  down  a  railway 

at  Hetton,  and  next  to  Darlington  for  a  like  purpose ;  and  I  finished 

both   railways.     After  that  I  went  to  Liverpool  to  plan  a  line  to 

Manchester.     The  directors  of  that  undertaking  thought  ten  miles 

an  hour  would  be  a  maximum  speed  for  the  locomotive  engine,  and 

I  pledged  myself  to  attain  that  speed.     I  said  I  had  no  doubt  the 

locomotive  might  be  made  to  go  much  faster,  but  we  had  better  be 

moderate  at  the  beginning.     The  directors  said  I  was  quite  right; 

for  if,  when  they  went  to  parliament,  I  talked  of  going  at  a  greater 

rate  than  ten  miles  an  hour,  I  should  put  a  cross  on  the  concern ! 

It  was  not  an  easy  task  for  me  to  keep  the  engine  down  to  ten 

miles  an  hour ;  but  it  must  be  done,  and  I  did  my  best.     I  had  to 


HISTORY   OF   THE   STEAM-ENGINE.  \[^ 

place  myself  in  the  most  unpleasant  of  all  positions — the  witness- 
box  of  a  parliamentary  committee.  I  was  not  long  in  it,  I  assure 
you,  before  I  began  to  wish  for  a  hole  to  creep  out  at.  I  could  not 
find  words  to  satisfy  either  the  committee  or  myself,  or  even  to  make 
them  understand  my  meaning.  Some  said:  /He's  a  foreigner.' 
'  No,'  others  replied  ;  '  he's  mad.'  But  I  put  up  with  every  rebuff 
and  went  on  with  my  plans,  determined  not  to  be  put  down.  Assist- 
ance gradually  increased ;  great  improvements  were  made  in  the 
locomotive;  until  to-day,  a  train  which  started  from  London  in  the 
morning  has  brought  me  in  the  afternoon  to  my  native  soil,  and 
enabled  me  to  meet  again  many  faces  with  which  I  am  familiar,  and 
which  I  am  exceedingly  pleased  to  see  once  more." 

Besides  planning  several  railways  after  this  period,  and  giving 
evidence  respecting  projects  of  this  kind  before  parliamentary  com- 
mittees, Stephenson  several  times  visited  the  continent  to  be  con- 
sulted respecting  lines  of  railway ;  on  one  of  which  occasions  he 
had  an  interview,  along  with  his  friend  Mr.  Sopwith,  with  the  king 
of  the  Belgians.  He  likewise  continued  to  be  a  prominent  man  at 
public  demonstrations  connected  with  the  opening  of  railways,  one 
of  the  latest  of  these  festivities  being  at  the  opening  of  the  Trent 
Valley  line  in  June  1847,  when  he  was  complimented  by  Sir  Robert 
Peel,  and  compared  by  him  to  Julius  Agricola,  the  maker  of  Roman 
roads  in  Britain.  George  was  now  accustomed  to  the  language  of 
compliment  from  classes  of  men  who  formerly  treated  his  theories 
with  derision.  In^replying  to  Sir  Robert  Peel's  flattering  remarks, 
he  could  not  refrain  from  noticing  this  change  of  sentiment. 
"  When,"  he  said,  "  I  look  back  to  the  time  when  I  first  projected  a 
locomotive  railway  in  this  neighborhood,  I  cannot  but  feel  aston- 
ished at  the  opinions  which  then  prevailed.  We  were  told,  even  by 
celebrated  engineers,  that  it  would  be  impossible  ever  to  establish 
railways.  Judge,  then,  how  proud  must  now  be  the  feelings  of  one 
who,  foreseeing  the  results  of  railways,  has  risen  from  the  lower 
ranks  on  their  success  !  I  may  venture  to  make  a  reference  to 
what  the  Right  Honorable  Baronet  said  relative  to  Julius  Agricola 
and  a  direct  line.  If  Julius  Agricola  laid  down  the  most  direct 
lines,  it  must  be  recollected  that  he  had  no  heavy  goods-trains  to 
provide  for,  and  gradients  were  of  no  consequence.  The  line  that 
general  took  was  probably  very  good  for  his  troops,  where  the  hills 

would  serve  to  establish  his  watches ;  but  such  lines  would  be  in  no 
5 


Ix 


HISTORY   OF   THE    STEAM-ENGINE. 


way  applicable  at  the  present  day,  where  the  road  is  covered  with 
long  goods-trains  propelled  by  the  locomotive.  What  we  require 
now  is  a  road  with  such  gradients  that  locomotives  shall  be  able  to 
carry  the  heaviest  loads  at  the  least  expense.  The  Right  Honor- 
able Baronet  will  excuse  me  if  I  say  that  to  have  a  line  that  is 
direct  is  not  the  main  thing.  Had  he  studied  the  laws  of  practical 
mechanics  as  I  have  done,  he  would  doubtless  have  regarded  good 
gradients  as  one  of  the  most  important  considerations  in  a  railway." 
This  last  remark  has  been  amply  verified.  Railways  are  now  made 
with  gradients  which  would  not  formerly  have  been  attempted ;  but 
the  heavy  expense  incurred  on  account  of  fuel  and  tear  and  wear 
of  machinery  to  overcome  the  ascents  forms  a  serious  deduction 
from  revenue. 

At  home,  in  the  close  of  his  days,  George  Stephenson  occupied 
himself  with  his  birds  and  other  animals,  for  which  he  had  a  great 
fondness ;  nor  did  he  take  less  pleasure  in  his  garden  and  the  rear- 
ing of  flowers  and  vegetables.  Occasionally  he  visited  the  scenes 
of  his  youth  among  the  collieries  about  Newcastle,  at  all  times 
taking  an  interest  in  the  welfare  of  the  workmen,  and  never  feeling 
ashamed  of  recognizing  old  acquaintances.  Though  often  invited 
to  the  houses  of  persons  of  distinction,  he  acknowledged  he  had  no 
wish  to  figure  in  what  he  called  fine  company.  It  is  said  that  he 
was  beset  by  projectors  of  all  kinds  for  the  sake  of  his  advice ;  and 
that  the  young  likewise  besought  his  counsel  as  to  their  proposed 
professional  career,  which  he  gave  always  cheerfully,  except  when 
these  youthful  aspirants  were  affectedly  dressed,  and  put  on  airs 
contrary  to  George's  notions  of  propriety.  To  a  young  applicant 
of  this  stamp  his  candor  was  probably  not  very  agreeable,  but  may 
have  been  salutary.  "I  hope  you  will  excuse  me;  I  am  a  plain- 
spoken  person,  and  I  am  sorry  to  see  a  nice-looking  and  rather 
clever  young  man  like  you  disfigured  with  that  fine-patterned  waist- 
coat and  all  these  chains  and  fang-dangs.  If  I,  sir,  had  bothered 
my  head  with  such  things  when  at  your  age,  I  should  not  have  been 
where  I  am  now." 

With  this  love  of  simplicity,  and  universally  respected,  George 
Stephenson  closed  his  useful  career.  He  died  I2th  August,  1848, 
aged  6j.  In  the  preceding  sketch  we  have  touched  merely  on  the 
chief  incidents  in  his  biography,  which  we  commend  for  perusal  in 


HISTORY  OF   THE   STEAM-ENGINE. 


Ix 


XI 


either  of  the  admirable  works  composed  by  Mr.  Smiles.  The 
mantle  of  George  Stephenson  fell  on  his  son,  Robert;  and  how  he 
added  lustre  to  the  family  name  is  well  known.  Besides  several 
great  railway  undertakings,  of  which  he  was  engineer,  he  designed 
the  High  Level  Bridge  across  the  Tyne  at  Newcastle,  the  Conway 
and  Britannia  Tubular  Bridges  in  North  Wales,  and  that  still  more 
magnificent  work  of  art,  the  Tubular  Bridge,  nearly  two  miles  in 
length,  across  the  St.  Lawrence  at  Montreal — in  all  which  works, 
however,  he  was  ably  assisted  by  subordinates ;  nor  should  it  be 
omitted  that  to  William  Fairbairn,  of  Manchester,  is  generally  im- 
puted the  invention  of  the  tubular  system  of  bridge-building.  In 
1844  he  entered  parliament  as  member  for  Whitby.  This  distin- 
guished son  survived  his  father  only  eleven  years.  He  died  in 
1859,  aged  56,  and  was  honored  with  a  public  funeral  and  interment 
in  Westminster  Abbey.  If  the  traveller  by  railway  wishes  to  see  a 
lasting  monument  to  George  and  Robert  Stephenson,  he  has  only 
to  look  around ! 


TREVETHICK's    circular    railway   at   LONDON,    1808. 


^     :B©SiiT  FCDLTON) 


THE  SHARE  AND  CLAIMS  OF  AMERICANS  AND 
OTHERS  IN  THE  DISCOVERY  AND  APPLICATION 
'OF   STEAM. 

The  main  story  related  above  is  from  English  records,  and  we 
have  deemed  it  necessary  to  glance  at  the  share  claimed  for  America 
in  this  important  introduction  of  steam  for  mechanical  purposes, 

iReviewing  the  history  of  the  discovery  of  steam,  as  described  in 
the  two 'biographies  given  above,  we  have  to  conclude  that,  although 
the  fact  of  steam  as  a  mighty  power  was  known  before  the  Christian 
era,*  yet  for  practical  use  it  was  worthless  till  Papin  made  his  dis- 


*  The  engineer,  noting  the  curious  things  in  bronze  and  in  copper,  exhumed  at  Pom- 
peii and  gathered  together  in  the  Museo  Borbonica  at  Naples,  will  linger  near  a  small 
vessel  for   heating  water,  little  more  than  a  foot  high,  in  which  are  combined  nearly  all 
the  principles  involved  in.the.modern  vertical  steam-boiler — fire-box,  smoke-fiue  through 
(Ixii) 


HISTORY   OF   THE   STEAM-ENGINE. 


Ixiii 


covery  as  related  at  page  xix,  supra.  Savary  seems  to  have  taken  it 
up  wliere  Papin  left  it,  and  Nevvcomen  improved  on  Savary,  till,  as 
we  see  at  page  xxiii,  supra,  Newcomen's  engine  fell  into  the  hands  of 
Watt  for  repair,  and  it  at  once  "became  a  living  thing."  The 
scramble  for  the  application  of  Watt's  disco «'ery  to  locomotives  and 
navigation,  whether  from  the  improved  experience  of  Savary  or 
Newcomen  or  the  perfected  discovery  of  Watt,  numbers  among  the 
scramblers  such  names  as  Murdoch,  Symington,  Miller,  Fitch, 
Rumsey,  Fulton,  Kingsley,Trevethick,  Telford,  Blenkensop,  Blackett, 
Ericsson,  Hackwah,  Bunstal,  and  several  in  France  and  Italy,  and 
the  culminating  success  of  the  result  of  all  these  competitors  was 


FITCH  S    STEAMBOAT. 


the  Rocket  locomotive  at  Rainhill,  and  Fulton's  steamboat,  the  Cler- 
mont, at  New  York. 

John  Fitch,  born  at  Windsor,  Conn.,  1743,  was  an  original 
genius.  In  1787  he  launched  a  steam-packet  (it  had  paddles  at  the 
side)  at  Philadelphia,  which  reached  a  speed  of  thirteen  miles  per 
hour,  and,  having  obtained  by  letters  patent  the  exclusive  right  of 
steam  navigation  in  New  Jersey,  Pennsylvania  and  Delaware,  he 
built  a  boat  to  convey  passengers  on  the  Delaware  river  for  hire, 
which  proved  a  commercial  failure.      He  died  1798. 

James  Rumsey  was  born  in  Maryland,  1743,  studied  mechanics 
and  became  an  inventor.     In  1784  (twenty-three  years  before  Fulton 

the  top  and  fire-door  at  the  side,  all  complete — and  strange  to  say,  this  little  thing  has  a 
water-grate,  made  of  small  tubes  crossing  the  fire-box  at  the  bottom,  an  idea  that  has 
been  patented  twenty  times  over,  in  one  shape  or  another,  within  the  period  of  the 
history  of  the  steam-engine. —  Joseph  Harrison,  "Jr. 


Jxiv  HISTORY  OF   THE   STEAM-ENGINE, 

built  the  Clermont)  he  exhibited  on  the  Potomac,  in  the  presence 
of  General  Washington,  a  boat  propelled  by  machinery.  In  1786 
he  exhibited  a  boat  in  which  a  pump  worked  by  steam-power  drove 
a  stream  of  water  from  the  stern  and  thus  furnished  the  motive- 
power.  A  society  was  formed  to  aid  his  project,  of  which  Franklin 
was  a  member.  His  death  occurred  in  1792,  while  he  was  making 
further  experiments. 

Apollos  Kingsley,  a  young  man,  of  Hartford,  Conn.,  about  the 
year  1798,  made  and  propelled  through  the  streets  of  that  city  a 
steam  locomotive,  which  he  then  said  would  in  future  be  the  means 
of  propelling  the  mail  stages,  etc.  He  was  not  credited,  died  soon 
after,  and  all  then  went  for  nothing. 

Robert  Fulton  was  born  in  Pennsylvania,  1765.     He  received 
a  good  school  education.     When   he  was  old  enough  his  mother 
apprenticed  him  to  a  jeweller  in  Philadelphia.     In  addition  to  his 
labors  at  this  trade  he  devoted  himself  to  painting,  and  the  sale  of 
his  portraits  and  landscapes  enabled  him,  in  the  space  of  four  years, 
to  purchase  a  small  farm,  on  which  he  placed  his  mother,  his  father 
being  dead.     At  the  age  of  twenty-two  he  proceeded  to  London, 
where   he   studied  painting   under  West ;    but,  after  several  years 
spent  thus,  he  felt  that  this  was  not  his  true  vocation.     Accordingly, 
abandoning   painting,    he    applied    himself    wholly    to    mechanics. 
Some  works  he  performed  in  Devonshire  obtained  him  the  patron- 
age of  the  Duke  of  Bridgewater  and  likewise  that  of  the  Earl  of 
Stanhope.     Accepting  an  invitation  from  the  United  States  minister 
at  Paris,  he  proceeded  to  that  city  in   1796  and  remained  there  for 
seven   years,    devoting    himself    to    new   projects    and    inventions. 
Amongst  his  inventions  here  was  the  nautilus,  or  sub-marine  boat, 
intended  to  be  used  in  naval  warfare,  which  he  in  vain  sought  the 
French  government  to  accept.     Nor  was  he  more  successful  with 
the  British  government,  which  he  next  tried,  though  commissions 
were  appointed   in  both   cases  to  test  the  value  of  his  invention. 
Having  failed  in  this  matter,  he  next  turned  his  attention  to  a  sub- 
ject that  had  frequently  occupied  his  mind  before  and  about  which 
he  had  written  a  treatise  in   1793,  viz.,  the  application  of  steam  to 
navigation.     In  1803  he  constructed  a  small  steamboat,  and  his  ex- 
periments with  it  on  the  Seine  were  attended  with  great  success. 
He  returned  to  New  York  in    1806  and  pursued  his  experiments 
there.     In  1807  he  launched  a  steam-vessel,  the  Clermont,  upon  the 


HISTORY   OF   THE   STEAM-ENGINE. 


Ixv 


Hudson,  which  made  a  successful  start  in  the  presence  of  thousands 
of  astonished  spectators.  From  this  period  steamers  (for  the  con- 
struction of  which  Fulton  received  a  patent  from  the  Legislature) 
came  into  pretty  general  use  upon  the  rivers  of  the  United  States. 


Fulton's  steamboat,  1803. 

Although  Fulton  was  not  the  first  to  apply  steam  to  navigation,  as 
a  steam-vessel,  Symington's,  had  been  tried  upon  the  Forth  and 
Clyde  canal  as  early  as  1789,  and  Miller,  near  Dumfries,  1 790,  yet 
he  was  the  first  to  apply  it  with  any  degree  of  success  to  steam 


THE    CLERMONT,    1807. 

NAVIGATION.  His  reputation  was  now  firmly  established,  and  he  was 
employed  by  the  United  States  government  in  the  execution  of 
various  projects  with  reference  to  canals  and  other  words.  In  18 14 
he  obtained  the  consent  of  the  Legislature  to  construct  a  steam- 


Jxvi  HISTORY    OF   THE   STEAM-ENGINE. 

frigate,  which  was  launched  in  the  following  year.  Though  the 
labors  of  Fulton  were  attended  with  such  great  success,  various 
lawsuits  in  which  he  was  engaged  in  reference  to  the  use  of  some 
of  his  patents  prevented  him  from  ever  becoming  wealthy,  and 
anxiety,  as  well  as  excessive  application,  tended  to  shorten  his  days. 
His  death,  in  1815,  produced  extraordinary  demonstrations  of 
mourning  throughout  the  United  States. 

*  Oliver  Evans  was  born  1755  in  the  State  of  Delaware  and  was 
educated  in  the  common  schools  of  Philadelphia,  to  which  city  his 
parents  had  removed  shortly  after  his  birth.  He  was  apprenticed 
to  a  wheelwright,  and  when  twenty-two  years  old  he  invented  a 
machine  for  card  teeth,  which  superseded  hand  work.  In  his 
thirty-first  year,  1786,  Evans  petitioned  the  Legislature  of  Pennsyl- 
vania for  the  exclusive  right  to  use  his  improvements  on  flouring- 
mills  and  steam-carriages  in  Pennsylvania.  In  the  following  year 
he  presented  the  same  petition  to  the  Legislature  of  Maryland.  In 
the  former  case  he  was  only  successful  so  far  as  to  obtain  the  privi- 
lege for  the  mill  improvements,  his  representations  respecting  steam- 
carriages  savoring  too  much  of  insanity  to  deserve  notice. 

He  was  more  fortunate  in  Maryland,  for  although  the  steam  pro- 
ject was  laughed  at,  yet  one  of  his  friends,  a  member,  very  judi- 
ciously observed  that  the  grant  could  injure  no  one,  for  he  did  not 
think  that  any  man  in  the  world  had  ever  thojight  of  such  a  thing 
before.  He  therefore  zuished  the  encouragement  might  be  afforded,  as 
there  was  a  prospect  of  its  producing  something  usefid.  The  exclu- 
sive privilege  was  granted,  and  after  this  Mr.  Evans  considered  him- 
self bound  in  honor  to  the  State  of  Maryland  to  produce  a  steam- 
carriage  as  soon  as  his  means  would  permit  him. 

To  Oliver  Evans  must  be  awarded  the  credit  of  having  built  and 
put  in  operation  the  first  practically  useful  high-pressure  steam-en- 
gine, using  steam  at  lOO  pounds  pressure  to  the  square  inch,  or 
more,  and  dispensing  with  the  complicated  condensing  apparatus  of 
Watt.f  The  high-pressure  engine  of  Evans  had  advantages  for  us 
in  its  greater  simplicity  and  cheapness,  and  ever  since  his  day  it  has 
continued  the  standard  steam-engine  for  land  purposes  in  America. 


*  We  are  indebted  for  this  notice  of  Oliver  Evans  to  a  valuable  work,  The  Locomotive 
Ens;ine  and  Philadelphia' s  Share  in  its  Early  Itnprovement,  by  Joseph  Harrison,  Jr. 
f  Watt's  patent  for  the  condensing  apparatus  was  dated  1 766. 


HISTORY   OF   THE   STEAM-ENGINE.  Ixvii 

English  writers  have  tried  to  detract  from  the  fame  of  Oliver 
Evans,  but  it  is  well  known  that  early  in  his  engineering  life  he  sent 
drawings  and  specifications  of  his  engines,  etc.,  to  England  by  the 
hands  of  Mr.  Joseph  Stacey  Sampson,  of  Boston.  It  is  well  known 
also  that  these  drawings,  etc.,  were  shown  to  and  copied  by  en- 
gineers in  England,  and  from  this  period  dates  the  introduction 
into  Europe  of  the  first  really  useful  high-pressure  steam-engine, 
now  so  generally  applied  to  locomotive  and  other  purposes. 

Basing  his  hopes  of  success  on  the  use  of  the  high-pressure  en- 
gine in  his  steam-carriage,  Oliver  Evans,  notwithstanding  the  oppo- 
sition and  even  the  derision  of  his  best  friends,  and  of  almost  every 
one,  made  earnest  efforts  in  the  beginning  of  this  century  to  carry 
out  his  design  for  building  his  favorite  machine,  but  without  suc- 
cess. He  had  a  good  friend  in  Mr.  Robert  Patterson,  the  Professor 
of  Mathematics  in  the  University  of  Pennsylvania,  who  recom- 
mended the  plan  as  highly  worthy  of  notice  and  who  wished  to  see 
it  tried.  Evans'  plan  was  shown  to  Mr.  B.  H.  Latrobe,  a  scientific 
gentleman  of  great  eminence  in  his  day,  who  publicly  pronounced 
them  chimerical  and  who  attempted  to  demonstrate  their  absurdity 
in  his  report  to  the  American  Philosophical  Society  on  Stcain-En- 
gines,  in  which  he  also  undertook  to  show  the  impossibility  of  mak- 
ing steamboats  useful. 

In  Mr.  Latrobe's  report  Mr.  Evans  was  said  to  be  seized  with  the 
" steain  viania^'  which  was  no  doubt  most  true.  To  the  credit  of 
our  then  and  now  most  learned  society,  the  portion  of  Mr.  Latrobe's 
report  which  reflected  so  harshly  upon  Mr.  Evans  was  rejected,  the 
members  conceiving  that  they  had  no  right  to  set  up  their  opinions 
as  an  obstacle  in  the  way  of  an  effort  towards  improvements  that 
might  prove  valuable  for  transport  on  land.  The  society  did,  how- 
ever, admit  in  the  report  the  strictures  on  steamboats. 

Oliver  Evans  never  succeeded  in  constructing  a  steam-carriage 
such  as  he  had  contemplated.  It  was  commenced,  and  unaided  he 
spent  much  time  and  money  in  fruitless  efforts  to  complete  it. 
Finding  himself  likely  to  be  impoverished  if  he  persisted  in  the 
scheme,  he  finally  abandoned  it,  and  devoted  his  time  thereafter  to 
the  manufacture  of  his  high-pressure  steam-engine  and  his  improved 
milling  machinery.  Previously,  however,  to  the  final  abandonment 
of  his  favorite  project,  Oliver  Evans,  on  the  25th  of  September,  1804, 
submitted  to  the  Lancaster  Turnpike  Company  a  statement  of  the 


XVlll 


HISTORY   OF   THE   STEAM-ENGINE. 


cost  of  and  probable  profits  of  a  steam-carriage  to  carry  one  Imndred 
barrels  of  ?iov\x  fifty  miles  in  twenty-four  hours,  tending  to  show  also 
that  one  such  carriage  would  make  more  net  profit  on  a  good  turn- 
pike road  than  ten  wagons  drawn  by  five  horses  each. 

He  offered  to  build  a  steam-carriage  at  a  very  low  price.  Evans' 
statement  to  the  turnpike  company  closed  as  follows :  "  It  is  too 
much  for  an  individual  to  put  in  operation  every  improvement  which 
he  may  invent.  I  have  no  doubt  but  that  "my  engines  will  propel 
boats  against  the  currents  of  the  Mississippi,  and  wagons  on  turnpike 
roads  with  great  profit.  I  now  call  upon  those  whose  interest  it  is, 
to  carry  this  invention  into  effect." 

Oliver  Evans,  in  the  early  part  of  1804,  came  nearest  to  realizing 


OLIVER    EVANS         ORUCTOR    AMPHIBOLIS 


his  favorite  idea,  in  obtaining  an  order  from  the  Board  of  Health  of 
Philadelphia  to  construct  at  his  foundry  (a  mile  and  a  half  from  the 
water)  a  dredging  machine  for  cleaning  docks,  the  first  one  ever  con- 
trived for  dredging  by  steam,  now  so  common. 

To  this  machine  Evans  gave  the  name  of  "  Oructor  Amphibolis," 
or  Amphibious  Digger,  and  he  determined,  when  it  was  completed, 
to  propel  it  from  his  work  shop  to  the  Schuylkill  river,  which  was 
successfully  done,  to  the  astonishment  of  a  crowd  of  people  gathered 
together  to  see  it  fail.  When  launched,  a  paddle-wheel,  previously 
arranged,  was  put  in  motion  at  the  stern,  and  again  it  was  propelled 
by  steam  to  the  Delaware,  leaving  all  vessels  half-way  behind  in  the 
trip,  the  wind  being  ahead. 


HISTORY   OF   THE   STEAM-ENGINE.  j^Jx 

This  result  Evans  hoped  would  have  settled  the  minds  of  doubters 
as  to  the  value  of  steam  as  a  motor  on  land  and  water.  But  his  at- 
tempt at  moving  so  great  a  weight  on  land  was  ridiculed,  no  allow- 
ance being  made  by  the  hindei-ers  of  that  day  for  tlie  disproportion 
of  power  to  load, — rudeness  in  applying  the  force  of  steam  for  its 
propulsion,  or  for  the  ill  form  of  the  boat.  A  rude  cut  of  the 
"  Oructor  Amphibolis"  is  still  extant,  which  shows  a  common  scow, 
mounted  on  four  wooden  wheels,  with  power  applied  to  the  whole 
number  of  the  wheels  by  the  use  of  leathern  belts. 

Evans,  after  this  experiment,  willing  to  meet  the  question  in  any 
way,  silenced  the  calipers  around  him  by  offering  a  wager,  that  for 
^3,000  he  would  make  a  steam-carriage  that  would  run  on  a  level 
road  as  swift  as  the  fastest  horse  they  could  produce.  His  bet  met 
with  no  takers. 

This  movement  by  steam  power  of  Oliver  Evans'  dredging  ma- 
chine on  land  was,  without  any  doubt,  the  first  application  of  steam 
to  a  carriage  in  America,  and  in  fact  the  first  locomotive  engine,* 
It  was  a  more  important  experiment  than  any  that  had  preceded  it, 
anywhere  in  the  same  direction. 

Oliver  Evans'  conceptions  respecting  the  power  of  steam,  many 
of  them  practically  exemplified  by  him,  reflect  great  credit  on  his 
sagacity  as  an  engineer,  and  many  of  his  predictions  in  regard  to  its 
great  value,  particularly  for  land  transport,  may  well  be  termed 
prophetic. 

In  the  early  part  of  this  century  he  publicly  stated  that  "  The  time 
will  come  when  people  will  travel  in  stages  moved  by  steam-engines 
from  city  to  city,  almost  as  fast  as  birds  fly, — fifteen  or  twenty  miles 
an  hour.  Passing  through  the  air  with  such  velocity,  changing  the 
scene  in  such  rapid  succession,  will  be  the  most  exhilarating  exer- 
cise." "  A  steam-carriage  will  set  out  from  Washington  in  the'  morn- 
ing,— the  passengers  will  breakfast  in  Baltimore, — dine  in  PJiiladel- 
phia,  and  sup  in  Nezv  York  the  same  day."  f  "  To  accomplish  this, 
two  sets  of  railways  will  be  required,  laid  so  nearly  level  as  not  to 
deviate  more  than  two  degrees  from  a  horizontal  line, — made  of  wood 
or  iron,  on  smooth  paths  of  broken  stone  or  gravel,  with  a  rail  to 

*  Du  Cognot's  carriage  was  made  in  1770 ;  see  page  xlviii.  Mr.  Harrison  probably  was 
not  aware  of  this. 

f  We  now  (1888)  lunch  at  2  o'clock  in  Washington,  and  dine  at  8  o'clock  the  same 
afternoon  in  New  York. 


Ixx  HISTORY   OF   THE   STEAM-ENGINE. 

guide  the  carriages,  so  that  they  may  pass  each  other  in  different 
directions,  and  travel  by  night  as  well  as  day." 

Much  stress  is  laid  upon  these  early  efforts  of  Oliver  Evans 
towards  the  introduction  of  steam  for  land  and  water  transporta- 
tion, and  much  space  has  been  given  here  to  set  them  forth.  With 
no  light  to  guide  him  (for  it  is  fair  to  suppose  that  he  knew  nothing 
of  the  little  that  had  been  done  up  to  his  day  in  Europe),  how  his 
trumpet-tones  ring  out  in  the  words  above  quoted  (date  1804),  com- 
pared with  the  "uncertain  sound"  made  by  the  English  engineers 
in  1829.  Tliey,  with  a  quarter  of  a  century  of  later  experience, 
during  which  period  much  had  been  done  to  improve  and  develop 
the  locomotive  engine,  then  no  new  thing,  nor  was  it  barren  of  use- 
ful practical  results,  hesitated  and  doubted  in  their  course.  He,  with 
no  misgivings  as  to  the  future,  and  with  no  dimmed  vision,  saw  with 
prophetic  eyes  all  that  we  now  see.  To  him  the  present  picture,  in 
all  its  grandeur  and  importance,  glowed  in  broad  sunlight.  In  the 
history  of  these  efforts  of  Oliver  Evans  it  is  noteworthy,  and  most 
creditable  to  our  sister  State  of  Maryland,  that  that  commonwealth 
extended  to  him  the  first  public  encouragement  in  his  steam-carriage 
project. 

Again  our  enterprising  neighbor  was  first  in  the  field,  since  be- 
come so  important,  for  we  find  that  in  March,  1827,  the  State  of 
Maryland  chartered  the  first  railway  company  in  America,  and  in 
1828  her  citizens  commenced  the  construction  of  the  Baltimore  and 
Ohio  Railway,  aiming  to  cross  the  Alleghenies;  certainly  the  greatest 
railway  scheme  that  had  been  thought  of  up  to  that  date,  and  now, 
in  its  completed  state,  a  triumph  of  railway  engineering.  To  this 
first  effort  to  make  a  great  railway  in  the  United  States,  and  its  in- 
fluence upon  the  history  of  the  locomotive,  reference  will  be  made 
hereafter. 

Oliver  Evans  died  in  18 19,  and  his  plans  for  a  steam-carriage  died 
with  him,  and  although  he  produced  nothing  practically  useful  in 
the  great  idea  of  his  life,  he  has  left  behind  him  an  enduring  monu- 
ment in  his  grain  and  flour  machinery. 

The  materials  for  the  history  of  the  next  attempt  at  making  a 
steam-carriage  in  America,  eight  or  nine  years  after  the  death  of 
Oliver  Evans,  are  not  very  full.  At  this  period  (1828)  a  steam-car- 
riage to  run  on  a  common  road  was  projected  by  some  parties  in 
our  city  whose  names  cannot  now  be  easily  reached.     This  steam- 


HISTORY   OF   THE   STEAM-ENGINE.  Jxxi 

carriage  was  built  at  the  small  engineering  establishment  of  Nicho- 
las and  James  Johnson,  then  doing  business  in  Penn  street,  in  the 
old  district  of  Kensington,  just  above  Cohocksink  creek,  Phila- 
delphia. 

An  &ye-witness  of  its  construction,  and  who  saw  it  running  under 
steam  on  several  of  its  trials,  describes  it  as  an  oddly-arranged  and 
rudely-constructed  machine.  It  is  believed  to  have  had  but  a  single 
cylinder,  set  horizontally,  with  connecting-rod  attachment  to  a  single 
crank  at  the  middle  of  the  driving-axle.  Its  two  driving-wheels 
were  made  of  wood,  the  same  as  an  ordinary  road-wagon,  and  were 
of  large  diameter,  certainly  not  less  than  eight  feet.  It  had  two 
smaller  wheels  in  front,  arranged  in  the  usual  manner  of  a  road- 
wagon,  for  guiding  the  movement  of  the  machine.  It  had  an  up- 
right boiler  hung  on  behind,  shaped  like  a  huge  bottle  ;  the  smoke- 
pipe,  coming  out  through  the  centre  at  the  top,  formed  the  neck  of 
the  bottle.  Its  safety-valve  was  held  down  by  a  weight  and  lever, 
and  it  was  somewhat  amusing  to  see  the  piiff,  p^^ff,  P^iff  of  the 
safety-valve  as  the  machine  jolted  over  the  rough  street.  This  was 
before  the  days  of  spring-balances  for  holding  down  the  safety-valves 
of  locomotives. 

On  its  trials,  made  on  the  unpaved  streets  of  the  neighborhood 
in  which  it  was  built,  this  steam-carriage  showed  an  evident  lack  of 
boiler  as  well  as  cylinder  power.  It  would,  however,  run  continu- 
ously for  some  time  and  surmount  considerable  elevations  in  the 
roads.  It  was  sometimes  a  little  unmanageable  in  the  steering- 
apparatus,  and  on  one  of  its  trials,  in  running  over  the  High  bridge 
and  turning  up  Brown  street,  its  course  could  not  be  changed  quick 
enough,  and  before  it  could  be  stopped,  it  had  mounted  the  curb- 
stone, smashed  the  awning-posts,  and  had  made  a  demonstration 
against  the  bulk-window  of  a  house  at  the  southwest  corner  of 
Brown  and  Oak  streets. 

After  this  mishap  it  was  not  seen  on  the  streets  again,  nor  is  it 
knowfi  what  ultimately  became  of  it.  This  last  effort  may  be  classed 
in  some  respects  no  doubt  with  what  Oliver  Evans  promised  in  his 
mind  to  carry  out,  and  it  is  very  evident  that  up  to  its  time  no  great 
amount  of  knowledge,  or  of  practical  or  theoretical  skill,  had  been 
brought  to  bear  upon  the  construction  of  locomotives  in  Philadel- 
phia. No  books  were  as  yet  published  in  America  describing  the 
locomotive,  or  telling  what  had  been  done  in  land  transport  by 


Ixxii  HISTORY  OF   THE   STEAM-ENGINE. 

steam  in  Europe.  The  trials  on  the  Liverpool  and  Manchester 
Railway  in  1829  had  not  been  made,  and  a  better  result  could  have 
hardly  been  expected  than  this  recorded  above. 

With  the  wonderful  success  of  the  Rocket  in  October,  1829,  the 
attention  of  our  engineers  and  capitalists  was  strongly  turned 
towards  this  new  revelation  in  land  transport,  that  had  so  suddenly 
flashed  upon  the  world.  It  was  a  matter  of  the  greatest  importance 
to  us,  with  our  rich  lands  everywhere  teeming  with  produce,  the 
producers  meanwhile  crying  aloud  for  better  means  to  get  their 
harvests  to  market,  and  for  getting  our  people,  too,  more  speedily 
from  point  to  point,  that  we  should  know  more  of  this  new  thing, 
and  if  it  fulfilled  its  promise,  to  get  the  advantage  of  it  as  soon  as 
possible. 

It  is  true  that  the  river,  the  canal,  and  the  turnpike  road  have  done 
good  service  in  the  past;  but  they  did  not  keep  pace  with  the  grow- 
ing wants  of  the  country.  The  river.  Nature's  own  free  highway, 
is,  when  navigable,  often  hindered  by  flood  and  frost,  by  currents 
and  by  drought,  nor  does  it  run  everywhere,  or  always  where  it 
would  best  conduce  to  man's  use  and  benefit.  The  slow,  plodding 
canal  did  its  work  cheaply,  and  with  nothing  better  it  must  have 
continued  the  favorite  means  for  inland  trade.  But  canals  are  only 
possible  where  water  can  be  had  in  abundance  to  keep  them  full, 
and  with  winter's  cold  to  interrupt  their  movement,  they  are  prac- 
tically useless  for  half  the  year.  Their  capacity,  at  best,  is  limited, 
too,  in  many  ways.  The  turnpike  road,  most  useful  in  its  place,  had 
a  very  narrow  limit  of  usefulness,  when  the  means  to  do  the  carry- 
ing trade  of  a  continent  were  to  be  attained.  Man's  restless  nature 
longed  for  and  demanded  something  better  than  the  river,  the  canal, 
or  the  turnpike  road,  and  this  had  been  found  in  the  Railroad  and 
the  Locomotive.  It  did  not  take  long,  therefore,  to  come  to  a 
decision  that  railways*  must  be  built,  and  the  locomotive  brought 
into  use,  and  that  speedily. 


*  The  first  railroad  built  in  America  was  on  Beacon  Hill,  near  Boston,  Mass.,  in 
1807.  It  was  built  by  Silas  "Whitney  to  haul  gravel  from  the  top  of  the  hill  to  the  bot- 
tom, and  consisted  of  two  tracks.  The  next  was  from  Thomas  Leiper's  stone-quarries 
en  Crum  creek,  Delaware  county,  Pa.,  to  his  landing  on  Ridley  creek,  a  distance  of  about 
one  mile,  in  1809.  The  next  railroad  (five-foot  gauge)  was  that  from  the  granite- quar- 
ries at  Quincy  to  the  Neponset  river  in  Massachusetts,  a  distance  of  about  three  miles, 
which  was  commenced  in  1826  and  finished  in  1827.     In  January,   1826,  was  com- 


HISTORY   OF   THE   STEAM-ENGINE.  Ixxiil 

It  has  been  seen  that  Maryland  took  the  lead,  and  she  had  her 
great  road  well  under  way  before  other  States  looked  the  question 
fairly  in  the  face.  South  Carolina  followed  the  lead  of  Maryland, 
and  granted  a  charter  at  an  early  period  to  the  South  Carolina 
Railway,  intending  to  cross  the  whole  breadth  of  the  State,  and 
ultimately  aiming  to  reach  the  far  west.  ^ 

Signs  of  railway  movement  were  seen  in  Pennsylvania,  Delaware 
and  New  Jersey,  and  in  New  York  and  New  England.  The  Colum- 
bia Railroad  (a  State  work)  was  projected  in  Pennsylvania  at  this 
time,  and  the  Philadelphia,  Germantown  and  Norristown  Railroad 
was  begun  in  Philadelphia.  New  Jersey  had  chartered  and  com- 
menced her  road  from  Camden  to  Amboy,  and  little  Delaware, 
ahead  of  all  the  States  north  and  east  of  her,  had  two  miles  of  the 
Newcastle  and  Frerichtown  Railroaa  ready  for  use  on  the  4th  of 
July,  1831. 

The  South  Carolina  Railroad  was  amongst  the  first  to  encourage 
the  manufacture  of  American  locomotives,  and  Mr.  Horatio  Allen, 
one  of  the  first  engineers  of  the  country,  designed  and  had  built, 
in  1830-31,  at  the  West  Point  foundry  in  New  York,  the  first  loco- 
motives it  is  believed  that  were  ever  ordered  and  made  in  the 
United  States  for  regular  railroad  traffic 

Other  engines  subsequently  built  in  New  York  after  designs  by 


menced  the  novel  "mule-road,"  nine  miles  in  length,  connecting  the  Summit  Hill  coal- 
mines, back  of  Mauch  Chunk,  with  the  Lehigh  river.  It  was  in  operation  May,  1827. 
On  August  8,  1829,  the  first  locomotive  that  ever  turned  a  driving-wheel  on  a  railroad- 
track  in  America  was  run  at  Honesdale,  Pa.,  on  the  newly-finished  road  that  connected 
the  Lackawanna  coal-fields  with  tide  water  on  the  Hudson  Canal.  The  road  in  question 
was  the  first  of  any  general  commercial  importance  ever  built  in  this  country,  and 
inaugurated  the  economical  system  of  inclined  planes,  since  adopted  by  engineers 
wherever  practicable.  It  is  claimed  by  some  that  at  about  the  same  time  Peter  Cooper, 
of  New  York,  built  the  first  American  locomotive — the  Tom  Thumb — in  1829,  and 
tried  it  on  the  Baltimore  and  Ohio  Railroad,  thirteen  miles  of  which  had  then  been 
laid.  It  did  not  work  quite  so  well  as  he  desired,  though  it  was  capable  of  locomotion, 
and  he  remodelled  it.  On  August  28,  1830,  it  made  a  perfectly  satisfactory  trip,  running 
thirteen  miles  in  an  hour  and  a  quarter.  The  Tom  Thwnb,  however,  was  only  an 
experiment.  The  first  American  locomotive  built  for  actual  service  was  the  Best 
Friend  of  Charleston,  ordered  March  i,  1830,  by  the  South  Carolina  Railroad  Com- 
pany, of  the  West  Point  Foundry,  New  York.  It  was  completed  in  October,  1830,  and 
shipped  to  Charleston.  It  made  its  trial  trip  November  2,  1830,  and  worked  satisfac- 
torily. The  second  American  engine  for  actual  service  was  built  by  the  same  parties  for 
the  same  company,  and  was  put  on  the  railroad  in  Marcli,  1831. — From  JVaison's 
Annals  of  Philadelphia. 


Ixxiv  HISTORY    OF   THE   STEAM-ENGINE. 

Mr.  Allen,  did  good  service  on  the  South  Carolina  Railroad,  and  it 
is  curious  to  note  that  in  these  later  engines  was  embodied  every 
valuable  point  of  the  Fairlie  engine,  now  making  so  much  noise 
in  England.  These  points  being  the  use  of  a  vibrating  truck  at 
both  ends  with  cylinders  thereon,  fire-box  in  the  middle,  with  flues 
from  fire-box  to  each  end  of  the  boiler,  double  smoke-box  and 
double  chimney,  with  fire-door  at  the  side  of  fire-box,  flexible 
steam  and  exhaust  pipe,  etc.* 

The  directors  of  the  Baltimore  and  Ohio  Railroad  in  January, 
1 83 1,  by  advice  of  Mr.  Jonathan  Knight,  of  Pennsylvania,  still  tak- 
ing the  lead  in  the  railroad  movement,  and  with  the  desire  to  en- 
courage American  skill,  adopted  the  same  plan  that  had  been  so 
successfully  carried  out  at  Liverpool  in  1829  and  offered  a  premium 
of  ;$4,ooo  for  the  best  American  locomotive. 

At  this  period  in  this  history  more  mind  and  more  practical 
knowledge  had  been  brought  out  in  Philadelphia  aiming  towards 
the  improvementof  the  locomotive  engine.  In  March,  1830,  Colonel 
Stephen  H.  Long,  of  the  United  States  Topographical  Engineers,  a 
gentleman  of  high  scientific  culture  and  noted  for  his  originality, 
obtained  a  charter  from  the  State  of  Pennsylvania,  incorporating  the 
"American  Steam-Carriage  Company,"  and  soon  thereafter  com- 
menced the  construction  of  a  locomotive  in  Philadelphia.  This  en- 
gine was  designed  somewhat  after  the  then  recently  improved  loco- 
motives made  in  England,  but  had  several  original  points. 

This  first  engine  of  Colonel  Long  was  placed,  when  finished,  upon 
the  Newcastle  and  Frenchtown  Railroad,  and  the  Hon.  Wm.  D. 
Lewis  has  furnished  the  following  account  of  its  trial  at  various 
times  on  that  road,  with  which  he  at  that  period  was  connected  in 
an  official  capacity. 


*The  first  locomotive  ever  run  on  a  railroad  in  America  was  undoubtedly  the 
Lion,  one  of  two  engines  built  at  Stourbridge,  in  England,  under  the  direction  of 
Mr.  Horatio  Allen  and  imported  into  this  country  in  the  autumn  of  1829  for  the  Dela- 
ware and  Hudson  Railroad  in  the  State  of  New  York.  Mr.  Allen,  in  describing  its 
first  movement,  says  that  he  was  the  only  person  upon  the  engine  at  the  time,  and  he 
certainly  made  the  first  trip  by  steam  on  an  American  railroad.  The  Lion,  built 
before  the  Rocket,  had  vertical  cylinders,  arranged  somewhat  after  the  manner  o\ 
the  old  style  of  Killingworth  or  Stockton  and  Darlington  engines,  with  four  driving- 
wheels,  all  connected.  The  boiler  of  this  engine  approached  closely  to  the  locomotive 
boiler  of  the  present  day,  in  having  a  fire-box  with  five  flues  leading  to  the  smoke-box, 
this  latter  feature  being,  in  fact,  the  first  step  towards  the  present  multi-tubular  boiler. 


HISTORY   OF   THE   STEAM-ENGINE.  \xXV 

COLONEL   long's   LOCOMOTIVE. 

"On  the  4th  of  July,  1831,  two  miles  of  rail  being  laid  on  the 
Newcastle  £,nd  Frenchtown  Railroad,  Colonel  Long  made  trial  on  it  of 
his  locomotive  which  weighed  about  three  and  one-half  tons.  The 
first  effort  was  not  a  success,  the  failure  being  attributed  to  lack  of 
capacity  to  furnish  a  sufficient  supply  of  steam.  It  would  go  well 
enough  for  a  while,  but  the  steam  could  not  be  kept  up.  The  next 
day  the  colonel  had  better  luck,  his  engine  then  going  to  the  end  of 
our  rails  and  back,  drawing  two  passenger  cars  packed  with  people 
(say  seventy  or  eighty)  with  apparent  ease,  and  it  had  fifty  pounds 
of  steam  at  the  end  of  the  experiment. 

"  The  colonel,  however,  was  not  satisfied  with  it,  and  the  machine 
was  brought  to  Philadelphia  again  and  a  new  boiler  was  constructed 
for  it  at  Rush  &  Muhlenburgh's  works  at  Bush  Hill.  This  engine 
was  again  taken  to  Newcastle  and  tried  upon  the  road,  but  it  again 
failed.  It  would  go  very  well  for  a  time,  but  on  the  31st  of  October, 
1 83 1,  a  pipe  was  burst  and  it  became  disabled.  This  being  repaired, 
two  days  thereafter  another  trial  was  made,  but  with  equal  want  of 
success,  which  was  ascribed  to  lack  of  power  as  well  as  of  specific 
gravity.  Alone  this  engine  went  very  well  and  rapidly,  say  at  the 
rate  of  twenty-five  miles  an  hour,  but  it  would  not  draw  a  satisfac- 
tory burden. 

"  Soon  after  the  above  date  Colonel  Long  removed  his  engine  from 
the  road  and  I  do  not  know  what  became  of  it  afterwards."  Mr. 
Lewis  adds :  "  The  above  memoranda  I  now  enclose  of  the  trials 
of  Colonel  Long's  locomotive  in  1 831  are  made  from  a  book  in  which 
all  the  facts  I  give  you  were  set  down  contemporaneously  with  their 
occurrence."  This  unsuccessful  attempt  of  Colonel  Long  was,  up  to 
its  date,  much  the  most  important  movement  that  had  yet  been 
made  in  Philadelphia  towards  the  improvement  of  the  locomotive, 
and  as  such  it  deserves  special  notice.  It  was  furthermore  not 
without  its  value  in  inducing  him  thereafter  to  pursue  the  subject  to 
much  better  results.  Had  Colonel  Long  more  faithfully  copied  the 
English  engine  of  his  day  he  would  have  had  better  success  in  his 
first  effort;  but  he,  as  with  all  our  Philadelphia  engineers  and  me- 
chanics at  that  time  and  in  the  succeeding  years,  aimed  at  making 
an  American  locomotive. 

Whilst  Colonel  Long  was  engaged  in  the  construction  of  his  engine 

Matthias  W.  Baldwin,  a  name  that  has  since  become  so  famous  in 
6 


Ixxvi  HISTORY   OF   THE   STEAM-ENGINE. 

the  history  of  the  improvements  and  in  the  manufacture  of  the  loco- 
motive in  Philadelphia,  was  engaged  in  making  a  model  locomotive 
for  the  Philadelphia  Museum.  In  this  work  Mr.  Baldwin  was  as- 
sisted by  that  highly  eminent  practical  mechanic  and  engineer, 
Franklin  Peale,  then  manager  of  the  museum. 

To  gratify  the  curiosity  of  the  public  to  know  more  of  this  new 
thing,  this  little  engine  was  placed  upon  a  track  laid  around  the 
rooms  of  the  museum,  in  what  was  then  the  Arcade,  in  Chest- 
nut street,  above  Sixth,  and  where  it  was  first  put  in  operation  on 
April  25,  1831.  It  made  the  circuit  of  the  museum  rooms  many 
times  during  the  day  and  evening  for  several  months,  drawing  be- 
hind it  two  miniature  passenger  cars,  with  seats  in  each  for  four 
persons,  but  often  carrying  twice  that  number,  in  a  manner  highly 
gratifying  to  the  public,  who  attended  in  crowds  to  witness  for  the 
first  time  in  this  city  and  State  the  effect  of  steam  in  railroad  trans- 
portation. This  little  engine  was  perhaps  the  first  made  expressly 
to  draw  passengers  that  had  ever  been  placed  on  a  railroad  in 
America.* 

With  the  knowledge  of  the  success  that  had  been  achieved  in 
England,  the  desire  to  know  more  of,  and  the  necessity  to  Jiave  as 
speedily  as  possible,  this  new  power  soon  became  a  paramount 
■question  in  the  Middle,  Northern,  Southern  and  Eastern  States  of 
the  Union. 

The  reward  of  ;^4,ooo  offered  for  the  best  American  locomotive 
by  the  directors  of  the  Baltimore  and  Ohio  Railroad,  brought  out 
many  competitors,  and  in  after  years  several  very  curious  specimens 
of  locomotive  engineering  might  be  seen  in  one  of  the  shops  of 

*In  rendering  a  just  meed  of  credit  to  all  who  aided  in  the  early  development 
of  the. locomotive  in  Philadelphia,  it  is  not  out  of  place  here  to  introduce  the  following 
extract  from  an  obituary  notice  of  Franklin  Peale,  read  before  the  American  Philo- 
sophical Society  at  a  meeting  on  December  16,  1870,  by  his  friend,  Robert  Patterson,  a 
grandson.of  Robert  Patterson,  who  had  been  Oliver  Evans'  firm  friend  in  the  latter's 
efforts  in  the  last  century  to  introduce  a  steam-carriage.  "  It  was  while  engaged  at  the 
museum  that  Mr.  Peale  placed  there  a  miniature  locomotive,  the  first  seen  in  this  country 
and  manufactured  by  his  friend,  M.  W.  Baldwin,  on  a  plan  agreed  upon  between  Mr. 
Peale  and  his  friend.  It  was  put  in  operation  on  a  track,  making  the  circuit  of  the  Ar- 
cade, in  which  the  museum  then  was,  drawing  two  miniature  cars  with  seats  for  four 
passengers.  The  valuable  aid  of  Mr.  Peale  was  afterwards  given  to  Mr.  Baldwin  in 
the  construction  of  the  locomotive  for  the  Philadelphia  and  Germantown  Railroad,  built 
in  1832,  the  success  of  which  led  to  the  establishment  of  Mr.  Baldwin  in  the  great 
business  oflJiis.life-rthefaundation  of  tke. Baldwin  Locomotive  Works." 


HISTORY   OF   THE   STEAM-ENGINE.  Ixxvli 

this  road.  An  eye-witness  of  these  efforts  in  1834  describes  one 
which  sported  two  walking  beams,  precisely  like  some  river  steamers 
of  the  present  day.  Mr.  Phineas  Davis,  of  York,  Pennsylvania, 
bore  off  the  prize  offered  by  the  Baltimore  and  Ohio  Railroad,  and 
his  engine  was  the  only  one  that  survived  the  trial.  With  the  Peter 
Cooper  upright  tubular  boiler  adapted  thereto,  this  locomotive  of 
Mr.  Davis  became  for  several  years  the  type  of  engine  for  the  road 
upon  which  it  won  its  fame,  and  to  this  day  some  of  these  Grass- 
hopper or  Crab  engines,  as  they  are  sometimes  called,  may  be  seen 
doing  good  service  at  the  Camden  Street  station,  in  Baltimore,* 

Philadelphia  mechanics,  following  the  lead  of  their  predecessors 
in  the  same  field,  entered  with  zeal  into  the  Baltimore  contest.  An 
engine  was  built  by  a  Mr.  Childs,  who  had  invented  a  rotary  engine 
which  in  a  small  model  promised  good  results,  and  an  engine  of 
about  fifty  horse-power  on  this  rotary  plan  was  built  and  sent  to 
Baltimore  for  trial.  A  record  of  its  performance  cannot  now  be 
easily  reached,  but  it  is  knov/n  that  it  was  never  heard  of  as  a 
practically  useful  engine  after  this  time. 

The  second  locomotive  built  in  Philadelphia,  to  compete  at  Bal- 
timore, was  designed  by  Mr.  Stacey  Costell,  a  man  of  great  origi- 
nality as  a  mechanic,  and  the  inventor  of  a  novelty  in  the  shape  of 
a  vibrating  cylinder  steam-engine  that  had  some  reputation  in  its 
day,  and  has  come  down  to  our  time  exactly  in  the  little  engine 
now  sold  in  the  toy-shops  for  a  dollar. 

The  Costell  locomotive  had  four  connected  driving-wheels,  of 
about  thirty-six  inches  in  diameter,  with  two  six-inch  cylinders  of 
twelve-inch  stroke.  The  cylinders  were  attached  to  right-angled 
cranks  on  the  ends  of  a  counter  shaft,  from  which  shaft  spur  gear- 
ing connected  with  one  of  the  axles.  The  boiler  was  of  the  Cornish 
type,  with  fire  inside  of  an  internal  straight  flue.  Behind  the  bridge 
wall  of  this  boiler,  and  inside  the  flue,  water  tubes  were  placed  at 
intervals,  crossing  each  other  after  the  manner  of  the  English  Gal- 


*  Previous  to  the  competition  on  the  Baltimore  Railroad,  Mr.  Peter  Cooper,  since  de- 
ceased, the  well-known  New  York  philanthropist,  sent  to  Baltimore  a  small  engine  not 
larger  than  an  ordinary  hand-car.  This  little  locomotive  had  an  upright  tubular  boiler 
(no  doubt  the  first  of  its  kind),  which  developed  such  good  steam-making  qualities  as 
to  induce  Mr.  Phineas  Davis  to  purchase  the  Cooper  patent  right,  and  boilers  of  thi^ 
kind  were  used  by  Mr.  Davis  in  the  locomotives  built  by  him  subsequent  to  the  com- 
petitive trial  on  the  Baltimore  and  Ohio  Railroad. 


Ixxviii  HISTORY   OF   THE    STEAM-ENGINE. 

loway  boiler  of  the  present  day.  The  peculiar  arrangement  of  this 
engine  made  it  possible  to  use  a  very  simple  and  efficient  mode  of 
reversement  by  the  use  of  a  disc  between  the  steam  pipe  and  the 
cylinders,  arranged  with  certain  openings  which  changed  the  direc- 
tion of  the  steam  and  exhaust  by  the  movement  of  this  disc  against 
a  face  on  the  steam  pipe  near  the  cylinder,  something  after  the 
manner  of  a  two-way  cock. 

It  is  not  known  whether  this  locomotive  of  Costell's  went  to  Bal- 
timore or  not.  It  is  known,  however,  to  have  been  tried  on  the 
Columbia  road  in  1833  or  1834,  but  its  success  was  not  very  strik- 
ing, and  it  was  subsequently  broken  up.  The  boiler  of  the  Costell 
locomotive  had  very  good  steam-making  qualities.  It  was  used  for 
a  long  time  as  a  stationary  engine  boiler. 

The  third  engine  begun  in  Philadelphia  for  the  Baltimore  trial  in 
1 83 1  was  after  a  design  of  Mr.  Thomas  HoUoway,  an  engineer  of 
some  reputation  forty  years  ago  as  a  builder  of  river  steamboat 
engines.     This  engine  was  put  in  hand,  but  was  never  completed. 

Something  was  gained  even  by  the  failures  that  are  here  related, 
and  these  early  self-reliant  efforts  show  with  what  tenacity  Philadel- 
phia engineers  clung  to  the  idea  of  building  an  original  locomotive, 
and  it  will  be  seen  hereafter  that  a  type  of  locomotive  essentially 
American  was  ultimately  the  result. 

Whilst  these  movements  towards  the  improvement  of  the  loco- 
motive were  going  on  amongst  us,  the  desire  to  have  the  railroad  in 
every  section  of  the  country  became  more  and  more  fully  confirmed. 
The  railway  from  Newcastle  to  Frenchtown,  sixteen  miles  in  length, 
was  finished  in  the  winter  of  1 831  and  1832,  and  two  locomotives 
built  by  Robert  Stephenson  at  Newcastle-upon-Tyne  were  imported 
to  be  run  upon  this  line,  which  made  then  an  important  link  in  the 
chain  of  passenger  travel  between  New  York  and  Washington,  In 
this  case,  as  in  several  others  in  the  early  history  of  the  railroad  in 
the  United  States,  this  new  element  came  in  as  an  adjunct  mainly 
of  the  river  steamboats,  and  was  considered  most  useful  in  super- 
seding the  old  stage  coach  in  connecting  river  to  river,  and  bay  to 
bay. 

That  the  railway  would  supersede  the  steamboat  for  passenger 
travel,  and  the  canal  for  heavy  transport,  was  not  dreamed  of  in  the 
early  day  of  the  new  power. 

When  the  English  locomotives  were  landed  at  Newcastle,  Del- 


HISTORY   OF   THE   STEAM-ENGINE. 


Ixxix 


aware,  it  became  necessary  to  select  a  skilled  mechanic  to  put  them 
together  as  speedily  as  possible.  Through  the  agency  of  Mr,  Wm. 
D.  Lewis,  a  most  active  director  of  the  Newcastle  and  Frenchtown 
Railroad  Company,  this  task  was  assigned  to  Matthias  W.  Baldwin. 
These  engines  were  of  the  most  improved  English  type,  and  were 
greatly  superior  in  design  and  workmanship  to  any  that  had  then 
been  seen  in  this  country.  In  putting  these  engines  together,  Mr. 
Baldwin  had  all  the  advantage  of  handling  their  parts  and  studying 
their  proportions,  and  in  making  drawings  therefrom.  This  proved 
of  great  service  to  him  when  he  received  an  order,  in  the  spring  of 
1832,  to  build  a  locomotive  for  the  Philadelphia,  Germantown  and 


THE   "old    ironsides,"    1832. 


Norristown  Railroad.  This  engine,  called,  when  finished,  the 
Old  Ironsides,  was  placed  upon  the  above  road  in  November, 
1832,  and  proved  a  decided  success.  Mr.  Franklin  Peale,  in  an 
obituary  notice  of  M.  W.  Baldwin,  writes :  "  that  the  experiments 
made  with  the  Ironsides  were  eminently  successful,  realizing  the 
sensation  of  a  flight  through  the  air  of  fifty  or  sixty  miles  an  hour." 
The  Old  Ironsides,  in  its  general  arrangement,  was  a  pretty  close 
copy  of  the  English  engines  on  the  Newcastle  and  Frenchtown 
Railroad,  but  with  changes  that  were  really  improvements.  The 
reversing  gear  was  a  novelty  in  the  locomotive,  although  the  same 
mode  had  been  long  used  for  steam  ferryboats  on  the  Delaware. 
This  arrangement  consisted  of  a  single  eccentric  with  a  double- 
latch  eccentric  rod,  gearing  alternately  on  pins,  on  the   upper  and 


l^^^  HISTORY    OF   THE   STEAM-ENGINE. 

lower  ends  of  the  arms  of  a  rock  shaft.  This  mode  of  reversing 
was  used  in  the  Baldwin  locomotives  for  many  years  after  the  0/d 
Ironsides  was  built. 

It  is  creditable  to  Mr.  Baldwin  as  an  engineer  that  the  Old 
Ironsides  was  the  first  and  last  of  his  imitations  of  the  English 
locomotives.  He,  following  the  bent  of  all  the  Philadelphia  engi- 
neers and  mechanics  that  had  entered  the  field,  aimed,  too,  at  mak- 
ing an  American  locomotive  ;  and  his  second  engine,  and  those 
succeeding  it,  were  entirely  different  in  design  from  the  Old  Ironsides. 

Following  the  success  of  this  first  locomotive,  other  orders  soon 
■flowed  in  upon  Mr.  Baldwin,  and  on  these  later  engines  many  val- 
uable improvements  were  introduced,  of  which  mention  will  be 
made  hereafter. 

Colonel  Stephen  H.  Long,  nothing  daunted  or  discouraged  by 
the  unsuccessful  results  of  his  first  engine  in  1831,  renewed  his 
efforts,  and  under  the  firm  of  Long  &  Norris,  the  successors  of  the 
American  Steam  Carriage  Company,  commenced  building  a  loco- 
motive in  1832,  subsequently  called  the  Black  Hazvk.  This  en- 
gine, when  finished,  was  run  for  some  time  on  the  Philadelphia  and 
Germantown  Railroad,  and  did  good  service  in  the  summer  of  1833, 
in  competition  with  Baldwin's  Ironsides.  The  Black  Hawk 
burnt  anthracite  coal  with  some  success,  using  the  natural  draught 
only,  which  was  increased,  for  the  first  time  in  a  locomotive,  by  the 
use  of  a  very  high  chimney,  arranged  to  lower  from  an  altitude  of 
at  least  twenty  feet  from  the  rails,  to  a  height  which  enabled  it  to 
go  under  the  bridges  crossing  the  railroad.  In  all  of  Colonel  Long's 
experiments  he  seems  to  have  discarded  the  steam  jet,  or  exhaust 
for  exciting  the  fire.  The  Black  Hawk  had  several  striking  pe- 
culiarities beside  the  one  just  mentioned.  The  boiler,  a  very  good 
and  a  very  safe  one,  was  unlike  any  that  had  preceded  it,  in  having 
the  fire-box  arranged  without  a  roof,  being  merely  formed  of  water 
sides,  and  in  being  made  in  a  detached  piece  from  the  waist  or 
cylindrical  part.  The  cylinder  portion  of  the  boiler  consisted  of 
two  cylinders  about  twenty  inches  in  diameter,  and  these,  lying 
close  together,  were  bolted  to  the  rear  water  side,  and  thus 
covered  the  open  top,  and  their  lower  half-diameters  thereby 
became  the  roof  of  the  fire-box.  A  notch  was  cut  half  way 
through  these  two  cylinders  on  their  lower  half  diameters,  about 
midway  of  the  length  of  the  fire-box,  directly  over  the  fire,  and 


HISTORY   OF   THE   STEAM-ENGINE.  IxXXl 

from  these  notches  flues  of  about  two  inches  diameter  passed 
through  the  water  space  of  each  cylinder  portion  of  the  boiler  to 
the  smoke-box.  These  flues  were  about  seven  feet  in  length.  Be- 
sides passing  through  the  flues,  the  fire  passed  also  under  the  lower 
halves  of  the  cylinder  portions  of  the  boiler,  a  double  sheet-iron 
casing,  filled  between  with  clay,  forming  the  lower  portion  of  the 
flue  and  connecting  it  with  the  smoke-box. 

The  Black  Hawk  rested  on  four  wheels,  the  driving-wheels, 
about  four  and  a  half  feet  diameter,  being  in  front  of  the  fire-box. 
The  guide-wheels  were  about  three  feet  diameter.  Inside  cylinders 
were  used,  and  these  required  a  double  crank  axle,  and  the  latter, 
forged  solid,  could  not  easily  be  had.  Colonel  Long  overcame  this 
difficulty  by  making  his  driving  axle  in  three  pieces,  with  two  bear- 
ings on  each,  and  with  separate  cranks  keyed  on  to  the  ends  of  each 
portion  of  the  axle,  with  shackle  or  crank  pins  arranged  after  the 
manner  of  the  modern  side-wheel  steamer  shafts. 

Flanged  tires  of  wrought  iron  could  not  then  be  had  easily,  and 
this  was  overcome  in  the  Black  Hawk  by  making  the  tread  for 
the  wheels  of  two  narrow  bands,  shrunk  side  by  side  on  the  wooden 
rim,  with  a  flat  ring,  forming  the  flange,  bolted  on  the  side  of  the 
wheel.  Springs  were  only  admissible  over  the  front  axle,  and  to 
save  shocks  in  the  rear,  the  after  or  fire-box  portion  of  the  boiler 
was  suspended  upon  springs.  The  camb  cut-off,  then  much  in  vogue 
on  the  engines  of  the  Mississippi  steamers,  was  used  in  the  Black 
Hawk.  Other  locomotives,  mainly  after  the  design  of  the  Black 
Hawk,  were  built  by  Long  &  Norris,  and  by  William  Norris  &  Co., 
in  1834,  but  they  were  not  greatly  successful. 

With  the  firm  of  William  Norris  &  Co.,  Colonel  Long  retired 
from  the  manufacture  of  locomotives  in  Philadelphia,  and  his  name 
was  not  thereafter  heard  of  in  connection  with  its  improvement.  On 
the  retirement  of  Colonel  Long,  William  Norris,  a  gentleman  then 
with  no  acknowledged  pretensions  as  a  mechanic  or  engineer, 
brought  other  skill  to  his  assistance,  and  after  several  not  very  suc- 
cessful efforts  with  engines  of  a  design  more  like  those  that  had 
succeeded  of  other  makers,  brought  out  an  engine,  in  1836,  called 
the  George  Washington,  the  success  of  which  laid  the  foundation 
of  the  large  business  done  for  thirty  years  thereafter  at  Bush  Hill, 
Philadelphia,  by  William  Norris,  and  subsequently  by  his  brother, 
Richard  Norris. 


Ixxxii  HISTORY   OF   THE   STEAM-ENGINE. 

The  George  Washington  was  a  six-wheel  engine  with  outside 
cylinders,  having  one  pair  of  driving-wheels,  four  feet  in  diameter, 
forward  of  the  fire-box,  with  vibrating  truck,  for  turning  curves,  in 
front.  This  engine  weighed  somewhat  over  fourteen  thousand 
pounds,  and  a  large  proportion  of  the  whole  weight  rested  on  the 
single  pair  of  driving  wheels. 

This  locomotive,  when  put  upon  the  Columbia  road  (now  Penn- 
sylvania Central),  did  apparently,  the  impossible  feat  of  running  up 
the  old  inclined  plane  at  Peter's  Island,  2,800  feet  long,  with  a  rise 
of  one  foot  in  fourteen,  drawing  a  load  of  more  than  nineteen  thou- 
sand pounds  above  the  weight  of  the  engine,  and  this,  too,  at  a  speed 
of  fifteen  miles  per  hour.  This  was  no  doubt  impossible,  if  the 
simple  elements  of  the  calculation  are  only  considered.  But  there 
was  a  point  in  this  experiment,  well  known  to  experts  at  the  time, 
which  did  make  it  possible,  even  by  calculation  ;  and  this  point  con- 
sisted in  the  amount  of  extra  weight  that  was  thrown  upon  the 
drivers  by  the  action  of  the  draft  link  connecting  the  tender  with  the 
engine, — the  result  being  that  about  all  the  weight  of  the  locomotive 
rested  upon  the  drivers,  less  the  weight  of  the  truck  frame  and 
wheels  in  front.  This  most  extraordinary  feat,  a  writer  on  the  sub- 
ject says,  "  took  the  engineering  world  by  storm,  and  was  hardly 
credited." 

The  George  Washington,  an  heir  of  the  earlier  efforts  of  Colonel 
Long,  was  unquestionably  a  good  and  well-made  engine,  and  greatly 
superior  to  any  that  had  preceded  it  from  the  Norris  Works.  The 
fame  this  engine  earned,  led  to  large  orders  in  the  United  States, 
and  several  locomotives  of  like  character  were  ordered  for  England 
and  for  Germany. 

Improvements  were  made  from  time  to  time  in  the  Norris  loco- 
motives— the  establishment  fairly  holding  its  own  with  its  rivals 
until  the  Norris  Works  ceased  to  exist  about  1866  or  %"].  Mr. 
William  Norris,  who  in  connection  with  Colonel  Long  had  founded 
the  works  at  Philadelphia,  at  one  time  commenced  the  building  of 
locomotives  at  Vienna,  Austria,  but  with  no  very  great  success  ;  and 
after  his  return  ceased  his  connection  with  the  Norris  Works.  At 
the  epoch  from  1833  to  1837,  the  Norris  and  Baldwin  engines  had 
each  their  advantages  and  defects. 

The  Norris  engine,  as  it  was  at  the  commencement  of  1837,  may 
be  described  as  follows :  The  boiler  was  of  the  dome  pattern,  known 


HISTORY   OF   THE   STEAM-ENGINE. 


Ixxxlii 


in  England  as  Bury's,  and  used  by  that  maker  in  1830;  the  framing 
was  of  wrought  iron.  The  cyhnders  were  placed  outside  of,  and 
were  fastened  to  the  smoke-box  as  well  as  to  the  frame.  The  engine 
was  supported  on  one  pair  of  driving-wheels,  placed  forward  of  the 
fire-box,  and  on  a  swivelling  four-wheeled  truck  placed  under  the 
smoke-box.  The  centre  of  the  truck  being  so  much  in  advance  of 
the  point  of  bearing  of  the  leading  wheels  in  the  English  engines 
of  that  day,  there  was  considerably  greater  weight  placed  upon  the 
driving-wheels  in  proportion  to  the  whole  weight,  while  it  was  not 
unusual  to  adjust  the  draw  bar  so  as  to  throw  a  portion  of  the  weight 
of  the  tender  upon  the  hinder  end  of  the  engine  when  drawing  its 
load.  These  engines  used  four  excentrics  with  latches.  Hand  levers 
were  used  for  putting  the  valve  rods  into  gear  when  standing.  The 
valve  motion  was  efficient,  as  the  performances  of  these  engines  fully 
attested. 

The  Baldwin  engine  of  the  same  period  had  a  similar  boiler,  and 
somewhat  similar  position  of  and  fastening  of  the  cylinders.  The 
driving-wheels  were  placed  behind  the  fire-box,  the  usual  truck 
being  placed  under  the  smoke-box.  These  engines  ran  steadily, 
owing  to  their  extended  wheel-base,  although  they  did  not  have  the 
weight  on  the  drivers,  and  the  consequent  adhesive  power  of  the 
Norris  engine.  The  framing  was  of  wood  covered  with  iron  plates, 
and  was  placed  outside  the  wheels. 

The  driving-wheels  had  two  outside  bearings.  The  cylinders, 
although  outside  of  the  smoke-box,  were  placed  so  as  to  give  a  con- 
nection to  the  crank  inside 
of  the  driving-wheels.  The 
crank  was  formed  in  the  driv- 
ing-axle, but  instead  of  being 
made  as  a  complete  double 
or  full  crank,  the  neck,  to 
which  the  connecting-rod 
was  attached,  was  extended 
through  and  fastened  into  a 
hole  in  the  driving-wheel, 
the  distance  from  the  centre 
being  equal  to  the  throw 
of  the  crank.  A  simple  straight  pin,  fitted  to  the  centre  of  the 
wheel,  and  extending  outwards,  formed  an  outside  bearing  for  the 


BALDWIN    ENGINE,    1 834. 


Ixxxiv  HISTORY   OF   THE    STEAM-ENGINE. 

axles.  This  device  of  Mr.  Baldwin's  was  most  ingenious  and 
efficient.  It  simplified  by  more  than  one-half  the  making  of  a 
crank-shaft,  and  increased  its  strength,  and  at  the  same  time  caused 
the  thrust  of  the  cylinder  to  act  close  to  the  driving-wheel  inside, 
in  the  same  manner  as  the  outside  crank-pin. 

With  the  introduction  of  the  outside  cylinder,  this  mode  of  mak- 
ing a  crank-axle  has  gone  into  disuse.  The  guide-bar  for  the  cross- 
head,  which  had  a  double  V  top  and  bottom,  was  clasped  by  the 
cross-head,  and  being  hollow  and  with  valve-chamber  attached,  was 
made  to  serve  the  purpose  of  a  force  pump.  The  valve-gear, 
already  described,  was  placed  under  the  foot-board,  and  although 
efficient,  was  cramped  for  room,  the  excentric  rods  consequently 
being  rather  too  short. 

In  workmanship  and  proportion  of  parts  the  Baldwin  engine  was 
the  superior  of  the  two  classes  of  locomotives  that  had  then  become 
in  their  manufacture  an  important  feature  in  the  trade  of  Phila- 
delphia. 

M.  W.  Baldwin,  in  1834  and  1837,  had  greatly  the  advantage  of 
the  Norris  establishment,  as  he  had  had  from^  the  first,  in  being  a 
good  practical  machinist  himself,  and  in  having  had  some  experience 
in  steam-engine  building  previous  to  the  making  of  the  Ironsides  in 
1832;  whereas,  William  Norris,  after  Colonel  Long  retired,  in 
1833-34,  having  personally  little  engineering  knowledge  and  no 
practical'  skill  in  engine  building,  was  left  entirely  dependent  upon 
hired  assistance,  which  at  that  time,  in  the  construction  of  the  loco- 
motive, was  most  difficult  if  not  almost  impossible  to  obtain. 

Mr.  Baldwin  had  also  the  great  advantage  of  better  workshops 
and  better  tools  than  his  early  competitor  at  the  commencement  of 
this  new  business;  hence  his  success  was  at  once  more  decided,  and 
the  improvements  in  his  locomotives,  both  in  design  and  in  work- 
manship, were  more  important  from  the  beginning.  It  is  needless 
to  speak  of  the  "  Baldwin  Locomotive  Works,"  Burnham,  Parry, 
Williams  &  Co.,  of  to-day. 

With  a  record  of  fifty  years,  during  the  early  period  of  which  it 
passed  successfully  through  many  vicissitudes,  it  maintains  its  well- 
earned  character  of  the  first  locomotive  manufactory,  both  in  quan- 
tity and  quality,  in  this  country;  and  it  is  doubtful  whether  it  is  not 
now  the  equal  to,  if  not  the  superior,  in  these  particulars,  of  any 
establishment  doing  similar  work  in  the  world. 


HISTORY   OF  THE   STEAM-ENGINE.  IxxXV 

The  Baldwin  engine  of  1837,  with  its  driving-axle  behind  the 
fire-box,  was  steady  at  high  speeds,  but  with  insufificient  adhesion 
to  the  rails. 

The  Norris  engine,  of  the  same  date,  having  a  great  proportion 
of  the  weight  overhanging  the  driving-axle,  and  having  adhesion 
equal  to  its  cylinder  power,  was  unsteady  on  the  rails.  Improvement 
rested  between  the  two  systems  of  Baldwin  and  of  Norris. 

In  the  spring  of  1835  the  firm  of  Garrett  &  Eastwick,  then  mak- 
ing steam-engines  and  light  machinery  in  Philadelphia,  desiring  to 
engage  in  this  new  business,  obtained  an  order  for  building  a  loco- 
motive engine  for  the  Beaver  Meadow  Railroad.  This  firm,  having 
no  practical  knowledge  of  locomotive  engine  building,  had  called 
to  their  assistance,  as  foreman,  Mr.  Joseph  Harrison,  Jr.,  a  young 
man  of  twenty-five,  with  ten  years'  experience  in  the  workshop,  and 
a  good  practical  workman,  who  had  been  employed  for  nearly  two 
years  as  a  journeyman  in  the  Norris  works,  and  who  when  there 
had  been  schooled  amidst  the  indifferent  successes  or  real  failures 
of  Long  &  Norris,  and  Wm.  Norris  &  Co.  The  first  locomotive 
designed  under  the  above  auspices  was  called,  when  finished,  the 
Samuel  D.  Ingliani^  after  the  President  of  the  road.  It  had  outside 
cylinder  connections,  then  not  much  in  vogue — running-gear  after 
the  Baldwin  type,  with  one  pair  of  driving-wheels  behind  the  fire- 
box, and  with  four-wheel  truck  in  front.  It  had  the  dome  or 
"Bury"  boiler. 

This  engine  had  some  points  about  it  which  differed  from  any 
locomotive  that  had  preceded  it.  Its  most  distinguishing  feature 
was  an  ingenious  and  entirely  original  mode  of  reversement,  in- 
vented and  patented  by  Mr.  Andrew  M.  Eastwick,  the  junior  mem- 
ber of  the  firm.  It  is  scarcely  possible  to  give  a  correct  idea  of 
this  device  without  a  model  or  drawings,  but  its  principle  consisted 
in  the  introduction  of  a  movable  block  or  slide,  called  a  reversing 
valve,  between  the  usual  slide  valve  and  the  opening  through  the 
cylinder  face.  This  reversing  valve  had  an  opening  through  it 
vertically  for  the  exhaust,  and  two  sets  of  steam  openings,  cor- 
responding, when  placed  opposite  thereto,  to  the  openings  on  the 
cylinder  face.  One  set,  called  direct  openings,  passed  directly 
through  the  valve,  and  when  fixed  for  going  forward  made  the  usual 
channels  to  the  cylinder.  The  second  set  of  openings  through  the 
reversing  valve,  called  indirect  openings,  coming  into  play  when  the 


IxXXvi  HISTORY   OF   THE   STEAM-ENGINE. 

engine  moved  backwards,  passed  from  the  upper  surface  of  this 
valve  but  half  way  through  it,  and  thence  were  diverted  laterally  to 
the  side  of  the  valve,  and  thence  along  the  side  and  again  laterally, 
came  out  of  the  under  side  where  the  reversing  valve  rested  against 
the  valve  face  of  the  cylinder,  directly  opposite  a  second  indirect 
opening  on  the  upper  surface  of  this  valve. 

When  the  reversing  valves  were  fixed  for  going  forward  the 
direct  openings  were  then  exactly  over  the  steam  openings  on  the 
cylinder,  whilst  the  indirect  openings  came  over  the  solid  surface  of 
the  cylinder  face  and  were  entirely  out  of  use.  The  exhaust  open- 
ing through  the  reversing  valve  in  this  case  came  directly  opposite 
the  exhaust  opening  on  the  cylinder.  The  slide  valve,  never  de- 
tached from  the  excentric,  moved  always  over  both  sets  of  open- 
ings in  the  usual  way.  Moving  the  reversing  valve  to  the  opposite 
end  of  the  steam  chest  from  where  it  had  been  placed  in  going  for- 
ward, and  the  case  was  different.  Then  steam  entering  the  revers- 
ing valve  at  the  upper  side,  instead  of  going  directly  into  the  cylin- 
der as  before,  was  diverted  in  the  manner  just  described  and  came 
out  at  the  cylinder  face  at  the  opposite  end  from  which  it  had  en- 
tered on  the  slide  valve  face  on  the  upper  side  of  the  reversing 
valve,  and  thus  the  direction  of  the  engine  was  changed  from  for- 
wards to  backwards,  or  vice  versa,  without  detaching  or  reattaching 
any  of  the  moving  parts  of  the  valve  gear. 

The  principle  and  action  of  Mr.  Eastwick's  invention  may  be 
guessed  at  from  what  has  been  described,  although  its  detail  may 
not  be  so  easily  made  out. 

This  new  arrangement,  neat  and  efficient  as  it  was,  had  its  de- 
fects, which  no  doubt  interfered  with  its  general  use.  It  increased 
by  the  thickness  of  the  reversing  block  the  length  of  the  steam 
openings  in  going  forward,  and  further  increased  their  length  in 
going  backwards.  It  also  prevented  the  use  of  a  long  lap  on  the 
slide  valve,  for  any  lead  of  the  excentric  in  going  forward,  causing 
a  corresponding  delay  in  receiving  steam  in  moving  backward.  In 
reviewing  these  defects  the  beauty  and  originality  of  Mr.  Eastwick's 
device,  must  not  be  overlooked. 

Nothing  for  the  same  purpose  so  novel  in  its  mode  of  action  had 
preceded  or  has  succeeded  this  invention  of  a  Philadelphia  mechanic, 
and  it  is  doubtful  whether  any  locomotive  has  since  been  made  with 
so  few  moving  parts  as  this  first  engine  of  Garrett  &  Eastwick. 


HISTORY   OF   THE   STEAM-ENGINE.  IxXXvH 

This  engine  had  for  the  first  time  the  rear  platform  covered  with  a 
roof  to  protect  the  engineman  and  the  fireman  from  the  weather. 

The  success  of  the  Samuel  D.  Ingham  was  quite  equal  to  any- 
locomotive  of  its  class  that  had  been  built  up  to  that  period  in 
Philadelphia,  and  orders  came  to  the  makers  from  several  sources 
for  others  of  the  same  kind. 

In  1836  Henry  R.  Campbell,  of  Philadelphia,  "in  order  to  dis- 
tribute the  weight  of  the  engine  upon  the  rails  more  completely," 
patented  the  duplication  of  the  driving-wheels,  placing  one  pair  be- 
hind and  one  pair  in  front  of  the  fire-box,  using  the  swivelling  truck 
in  front  of  Baldwin  and  others. 

Mr.  Campbell  subsequently  made  an  engine  after  his  patent, 
which  was  tried  on  the  Philadelphia  and  Germantown  Railroad,  and, 
although  not  a  decided  success,  it  was  a  great  step  in  the  direction 
in  which  improvement  was  most  needed.  Its  principal  defect  con- 
sisted in  its  having  no  good  means  of  equalizing  the  weight  on  the 
driving-wheels  so  as  to  meet  the  various  undulations  in  the  track. 

To  remedy  the  defects  in, the  Baldwin,  Campbell  and  Norris  en- 
gines Garrett  &  Eastwick  (soon  thereafter  changing  their  firm  to 
Garrett,  Eastwick  &  Co.,  Joseph  Harrison,  Jr.,  becoming  the  junior 
partner)  commenced  in.  the  winter  of  1836-7  a  new  style  of  locomo- 
tive for  the  Beaver  Meadow  Railroad  Company. 

Adopting  the  Campbell  plan  of  running  gear,  they  aimed  at 
making  a  much  heavier  engine  for  freight  purposes  than  had  yet 
been  used.  This  could  be  only  rendered  possible  on  the  slight 
roads  of  the  country  at  that  time  by  a  better  distribution  of  the 
weight  upon  the  rails. 

In  the  first  of  the  improved  engines  made  by  Garrett  &  Eastwick 
for  the  Beaver  Meadow  Railroad  Mr.  Andrew  M.  Eastwick  intro- 
duced an  important  improvement  in  the  Campbell  eight-wheel  en- 
gine, for  which  he  obtained  a  patent  in  1836.  This  improvement 
consisted  in  the  introduction  under  the  rear  end  of  the  main  frame 
of  a  separate  frame  in  which  the  two  axles  were  placed,  one  pair  be- 
fore and  one  pair  behind  the  fire-box.  This  separate  frame  was 
made  rigid  in  the  Hercules,  the  first  engine  in  which  it  was  used, 
and  vibrated  upon  its  centre  vertically,  and  being  held  together 
firmly  at  the  ends,  both  sides  at  all  times  moved  in  the  same  plane, 
thus  only  accommodating  the  undulations  in  the  track  in  a  perfect 
manner,  when    the   irregularities  were    on    both    rails    alike.     The 


Ixxxviii 


HISTORY   OF   THE   STEAM-ENGINE. 


weight  of  the  engine  rested  upon  the  centre  of  the  sides  of  this 
separate  frame  through  the  intervention  of  a  strong  spring  above  the 
main  frame,  the  separate  frame  being  held  in  place  by  a  pedestal 
bolted  to  the  main  frame,  the  centres  of  the  separate  frame  vibrat- 
ing upon  a  journal  sliding  vertically  in  this  pedestal. 

Mr.  Eastwick's  design  was,  however,  somewhat  imperfect  in  not 
accommodating  the  weight  of  the  four  driving-wheels  to  the  irregu- 
lar undulations  on  both  tracks.  There  were  other  minor  improve- 
ments in  the  Hercules,  one  of  which  was  the  introduction,  for  the 
first  time  into  steam  machinery,  of  the  bolted  stub-end  instead  of 


HENRY    R.    CAMPBELLS    FIRST    DESIGN    FOR   AN    EIGHT- 
WHEELED    LOCOMOTIVE,    1836. 

the  old-fashioned  and  unsafe  mode  of  gib  and  key  for  holding  the 
strap  on  the  connecting  rods.  This  device,  an  idea  of  Mr.  Harri- 
son's, is  now  universally  used  in  the  connecting  rods  of  the  loco- 
motive engine. 

Doubts  were  expressed  by  some,  and  amongst  them  not  a  few 
engine-builders,  that  the  Hercules,  weighing  2^iow\.  fifteen  tons,  would 
prove  too  heavy — that  this  engine  would  not  turn  curves  or  go 
into  switches  without  trouble,  etc.,  etc.,  but  Eastwick  &  Harrison 
had  good  friends  in  Captain  Matthew  C.  Jenkins,  a  director,  and 
Mr.  A.  Pardee,  the  chief-engineer  of  the  Beaver  Meadow  Railroad. 
They  had  committed  themselves  to  this  new  style  of  locomotive 


HISTORY   OF   THE   STEAM-ENGINE.  Ixxxix 

and  were  not  disposed  to  see  it  fail  for  lack  of  a  fair  trial.  They 
had  no  cause  to  regret  their  confidence  in  after  years.  At  the  time 
the  Hercules  was  placed  upon  the  Beaver  Meadow  Railroad  this  road 
had  a  flat  rail,  but  five-eighths  of  an  inch  thick  and  two  and  a  half 
inches  wide,  laid  upon  continuous  string-pieces  of  wood,  with  mud- 
sills underneath. 

The  Hercules,  when  put  in  operation  on  the  Beaver  Meadow  Rail- 
road, proved  a  great  success  and  led  to  other  orders  for  the  same 
class  of  engine.  This  division  of  the  weight  on  more  points  of  the 
road,  and  its  more  perfect  equalization  thereon,  seemed  at  the  time, 
as  it  has  proved  since,  to  have  been  the  commencement  of  a  new 
era  in  the  history  of  the  locomotive.  To  remedy  the  defect  incident 
to  Mr.  Eastwick's  plan,  as  before  mentioned,  in  these  early  eight- 
wheel  engines,  an  improvement  was  patented  in  1838  by  Joseph 
Harrison,  Jr.,  the  junior  partner  of  the  firm  of  Eastwick  &  Har- 
rison. 

Mr.  Harrison's  patent  showed  many  ways  of  carrying  out  the 
principle  of  his  improvement,  but  the  one  preferred  consisted  in 
placing  the  driving  axle  bearings  in  pedestals,  in  the  usual  manner, 
bolted  to  the  main  frame,  and  by  the  use  of  a  compensating  lever 
above  the  main  frame,  vibrating  on  its  centre,  at  the  point  of  attach- 
ment to  the  main  frame,  the  ends  of  this  lever  resting  on  the  axle- 
boxes  by  means  of  pins  passing  through  the  frame.  These  levers 
vibrated  on  each  side  of  the  engine  separately,  and  thus  met  all  the 
unevenness  in  both  rails  within  a  certain  prescribed  limit,  which  was 
governed  by  the  play  of  the  axle-boxes  in  the  pedestals. 

This  arrangement  of  Mr.  Harrison's  was  simpler,  lighter  and 
cheaper  than  the  one  that  had  preceded  it  and  was  used  in  all  the 
eight-wheel  engines  built  by  Eastwick  &  Harrison  after  the  second 
one. 

In  all  engines  now  built  in  this  country  or  in  Europe,  with  more 
than  six  wheels,  this  device  of  Mr.  Harrison  is  used  in  one  or  other 
of  the  different  ways  indicated  in  his  patent.  Mr.  Harrison's  pat- 
ent included  an  improvement  in  the  forward  truck,  making  it 
flexible,  so  that  it  would  accommodate  itself  to  irregular  undulations 
on  both  rails. 

The  engineers  and  manufacturers  of  this  period  did  not  at  once 
fully  understand  the  significance  of  the  innovation  so  successfully 
carried  out  by  Eastwick  &  Harrison.     They  clung  to  the  older  idea 


xc 


HISTORY  OF   THE   STEAM-ENGINE. 


that  one  pair  of  driving-wheels  was  quite  sufficient  whether  placed 
before  the  fire-box  or  behind,  nor  did  they  fairly  adopt  the  new  sys- 
tem until  after  its  value  had  been  fully  demonstrated  by  several 
years  of  trial. 

In  the  summer  of  1839  Eastwick  &  Harrison  received  an  order 
from  the  Philadelphia  and  Reading  Railroad  Company,  through 
the  chief-engineer,  Mr.  Moncure  Robinson,  for  a  freight  engine  that 
had  peculiar  points.  This  engine  was  designed  generally  upon  the 
Hercules  plan,  but  it  was  stipulated  in  the  contract  that  the  whole 
weight  should  be  eleven  tons  gross,  with  nine  to7is  on  the  four 
driving  wheels.  It  was  also  stipulated  that  it  should  burn  anthra- 
cite coal  in  a  horizontal  tubular  boiler. 


HERCULES, 
Garrett  &  Eastwick's  first  eight-wheeled  Locomotive,  1837,  as  arranged  with  "  Harri- 
son "  equalizing  levers. 

To  distribute  the  nine  tons  on  the  driving-wheels  the  rear  axle 
was  placed  under  the  fire-box  and  somewhat  in  advance  of  its  cen- 
tral line,  instead  of  being  behind  the  fire-box,  as  in  the  Hercules. 
This  arrangement  of  the  rear  axle  permitted  nine  tons  of  the  whole 
weight  of  the  engine  to  rest  on  the  four  driving-wheels.  The  boiler 
was  of  the  Bury  type,  and  the  fire-box  had  the  then  unprecedented 
length,  outside,  of  five  feet.  The  tubes,  two  inches  in  diameter  and 
only  five  feet  long,  were  more  numerous  than  usual  and  filled  the 
cylinder  part  of  the  boiler  almost  to  the  top.  Cylinders  12^ 
inches  in  diameter,  1 8-inch  stroke,  using  no  cut-off;  driving-wheels 


HISTORY   OF   THE   STEAM-ENGINE. 


XCl 


42  inches.  The  Gurney  draft-box  was  used  with  many  exhaust 
jets  instead  of  one  or  two  large  ones. 

It  is  believed,  that  in  this  engine  was  used,  for  the  first  time,  the 
steam-jet  for  exciting  the  fire  when  standing.  The  engine  here 
described,  called,  when  finished,  the  Gowaji  &  Marx,  after  a  Lon- 
don banking  firm,  excited  much  attention  in  the  railroad  world  by 
its  great  tractive  power,  compared  with  its  whole  weight. 

On  one  of  its  trips  (February  20,  1840)  it  drew  a  train  of  one 
hundred  and  one  four-wheeled  loaded  cars  from  Reading-  to  Phila- 


FREIGHT   ENGINE   "gOWAN   &    MARX,"    1 839. 

Designed  and  built  by  East  wick  &  Harrison,  Philadelphia,  for  the  Philadelphia  and 

Reading  Railroad,  1839.     Slightly  varied  from  the  original. 

delphia,  at  an  average  speed  of  9.824-  miles  per  hour,  nine  miles 
of  the  road  being  a  continuous  level.  The  gross  load  on  this  occa- 
sion was  423  tons,  not  including  the  engine  and  tender,  which,  if 
the  weight  of  the  tender  is  counted,  equalled  forty  times  the  weight 
of  the  engine. 

See  Journal  of  Franklin  Institute,  1840,  vol.  25,  page  99,  Report 
of  G.  N.  Nicols,  Superintendent  Philadelphia  and  Reading  Railroad, 
which  closes  as  follows :  "  The  above  performance  of  an  eleven-ton 
engine  is  believed  to  excel  any  on  record  in  this  or  any  other  coun- 
try." It  may  be  doubted  whether  it  has  been  excelled  since. 
7 


^^[[  HISTORY   OF   THE   STEAM-ENGINE. 

How  strangely  this  feat  of  the  Gowan  &  Marx  compares  with  the 
trials  on  the  Liverpool  and  Manchester  Railroad  in  October,  1829, 
but  ten  years  before,  when  all  that  was  required  of  the  competing 
locomotives  was  that  they  should  draw  about  three  times  their  own 
weight,  tender  included,  on  a  level  track,  five  miles  long,  especially 
prepared  for  the  trial.  The  great  success  of  the  Gowan  &  Marx 
induced  the  Philadelphia  and  Reading  Railroad  Company  to  dupli- 
cate the  plan  of  this  engine  in  ten  engines  subsequently  built  at 
Lowell,  Mass. 

In  1840  the  Gowan  &  Marx  attracted  the  particular  attention  of 
the  Russian  engineers.  Colonels  Melnikoff  and  Krafft,  who  had  been 
commissioned  by  the  Emperor  Nicholas  to  examine  into  and  report 
upon  the  various  systems  of  railroads  and  railroad  machinery  then 
in  operation  in  this  country  and  in  Europe. 

The  result  of  their  examination  was  favorable  to  the  American 
system,  and  when  the  engineers  above  named  made  their  report  on 
the  construction  of  a  railroad  from  St.  Petersburg  to  Moscow,  an 
engine  upon  the  plan  of  the  Gowan  &  Marx  was  recommended  as 
best  adapted  to  the  purposes  of  this  first  great  line  of  railroad  in 
the  Empire  of  Russia,  and  Eastwick  &  Harrison  were  requested 
to  visit  St.  Petersburg  with  the  view  of  making  a  contract  for  build- 
ing the  locomotives  and  other  machinery  for  the  road. 

Mr.  Harrison  went  to  St.  Petersburg  in  the  spring  of  1843,  and  in 
connection  with  Mr.  Thomas  Winans,  of  Baltimore,  a  contract  was 
concluded  with  the  government  of  Russia,  at  the  close  of  the  same 
year,  for  building  162  locomotives,  and  iron  trucks  for  2500  freight- 
cars.  Mr.  Eastwick  joined  Mr.  Harrison  and  Mr.  Winans  at  St. 
Petersburg  in  1844. 

Eastwick  &  Harrison  closed  their  establishment  in  Philadelphia 
in  1844,  removing  a  portion  of  their  tools  and  instruments  to  St. 
Petersburg,  and  there,  under  the  firm  of  Harrison,  Winans  &  East- 
wick, completed,  at  the  Alexandroffsky  Head  Mechanical  Works, 
the  work  for  which  they  had  contracted.  When  the  work  was 
commenced  under  the  contract  of  Harrison,  Winans  &  Eastwick 
with  the  Russian  government,  Joseph  Harrison,  Jr.,  designed  and 
had  built  under  his  own  supervision,  at  St.  Petersburg,  the  first 
machine,  it  is  believed,  that  was  ever  made  for  boring  out  the  holes 
for  right-angled  crank-pins  in  the  driving-wheels  of  locomotive 
engines.     This  right-angled  boring-machine,  on  precisely  the  same 


HISTORY   OF   THE    STEAM-ENGINE. 


XClll 


principle  as  devised  by  Mr.  Harrison,  has  since  become  indis- 
pensable in  every  locomotive  establishment.  The  same  idea  was 
partially  put  in  use  as  early  as  1838,  when  the  second  eight-wheel 
engine  Beaver  was  built  by  Garrett  &  Eastwick  for  the  Beaver 
Meadow  Railroad. 

The  first  contract  with  the  Russian  government  was  closed    in 
185 1,  at  which  time  a  second  contract  was  entered  into,  by  two 


HARRISON,    WINANS    &    EASTWICK  S    FREIGHT    ENGINE. 
Built  at  St.  Petersburg,  Russia,  for  the  St.  Peterlburg  &  Moscow  Railroad,  1844. 

members  of  the  firm,  for  the  repairs  to  the  rolling  stock  of  the  St. 
Petersburg  and  Moscow  Railroad,  which  continued  until  1862. 


]^ot€. — We  are  indebted  for  the  above  lengthy  and  vahiable  extract  to  a  work  published 
in  Philadelphia,  1872  (Geo.  Gebbie),  written  by  Joseph  Plarrison,  Jr. :  "  The  Locomotive 
and  Philadelphia's  Share  in  its  Early  Improvement."  Mr.  Harrison  was  one  of  the  ablest 
and  most  successful  mechanics  that  America  has  ever  produced  :  he  was  a  gentleman  of 
great  good  taste,  eminent  for  his  broad  views  and  liberal  patriotic  aid  in  all  good  works. 
He  was  born  in  Philadelphia  in  1810  and  died  there  1875. 


XCIV 


HISTORY   OF   THE   STEAM-ENGINE. 


[Having  in  a  brief  manner  brought  the  history  of  the  steam-engine  in  both  Europe 
and  America  forward  to  1842,  we  find  the  subject  suddenly  expand  beyond  all  hopes  of 
even  Iceeping  a  fair  report  of  the  various  establishments  started  for  the  manufacture  of 
boilers  and  steam-engines  of  every  description.  Not  only  every  country  has  many  pri- 
vate shops  and  factories,  but  nearly  every  railroad  company  has  its  own  machine-shops. 
In  order  to  bring  the  story  of  progress  forward  till  near  the  present  day,  we  will  as 
briefly  as  possible  notice  the  progress  of  locomotive  engine  building  at  the  Baldwin 
Locomotive  Works,  Philadelphia,  which,  being  the  largest  establishment  of  its  kind  'n 
the  world,  may  be  considered  a  representative  establishment.] 

In  1840  Mr.  Baldwin  received  an  order,  through  Augu.st  Belmont, 
Esq.,  of  New  York,  for  a  locomotive  for  Austria,  and  had  nearly 
completed  one  which  was  calculated  to  do  the  work  required  when 
he  learned  that  only  sixty  pounds  pressure  of  steam  was  admissible, 
whereas  his  engine  was  designed  to  use  steam  at  one  hundred 
pounds  and  over.  He  accordingly  constructed  another,  meeting 
this  requirement,  and  shipped  it  in  the  following  year.  This  engine, 
it  may  be  noted,  had  a  kind  of  link-motion,  agreeably  to  the  specifi- 
cation received,  and  was  the  first  of  his  make  upon  which  the  link 
was  introduced. 

Mr.  Baldwin's  patent  of  December  31,  1840,  covering  his  geared 
(engine,  embraced  several  other  devices,  as  follows: 

1.  A  method  of  operating  a  fan,  or  blowing-wheel,  for  the  purpose 
of  blowing  the  fire.  The  fan  was  to  be  placed  under  the  footboard, 
and  driven  by  the  friction  of  a  grooved  pulley  in  contact  with  the 
flange  of  the  driving-wheel. 

2.  The  substitution  of  a  metallic  stuffing,  consisting  of  wire,  for 
the  hemp,  wool,  or  other  material  which  had  been  employed  in 
stuffing-boxes. 

3.  The  placing  of  the  spnligs  of  the  engine-truck  so  as  to  obviate 
the  evil  of  the  locking  of  the  wheels  when  the  truck-frame  vibrates 
from  the  centre-pin  vertically.  Spiral  as  well  as  semi-elliptic  springs, 
placed  at  each  end  of  the  truck-frame,  were  specified.  The  spiral 
spring  is  described  as  received  in  two  cups — one  above  and  one 
below.  The  cups  were  connected  together  at  their  centres  by  a 
pin  upon  one  and  a  socket  in  the  other,  so  that  the  cups  could 
approach  toward  or  recede  from  each  other  and  still  preserve  their 
parallelism. 

4.  An  improvement  in.  the  manner  of  constructing  the  iron  frames 
of  locomotives,  by  making  the  pedestals  in  one  piece  with,  and  con- 
stituting part,  of,  the,  fr.anie;s. 


HISTORY   OF   THE   STEAM-ENGINE. 


XCV 


5.  The  employment  of  spiral  springs  in  connection  with  cylin- 
drical pedestals  and  boxes.  A  single  spiral  was  at  first  used,  but 
not  proving  sufficiently  strong,  a  combination  or  nest  of  spirals 
curving  alternately  in  opposite  directions  was  afterward  employed. 
Each  spiral  had  its  bearing  in  a  spiral  recess  in  the  pedestal. 

In  the  specification  of  this  patent  a  change  in  the  method  of 
making  cylindrical  pedestals  and  boxes  is  noted.  Instead  of  boring 
and  turning  them  in  a  lathe,  they  were  cast  to  the  required  shape 
in  chills.  This  method  of  construction  was  used  for  a  time,  but 
eventually  a  return  was  made  to  the  original  plan,  as  giving  a  more 
accurate  job. 

In  1842  Mr.  Baldwin  constructed,  under  an  arrangement  with  Mr. 
Ross  Winans,  three  locomotives  for  the  Western  Railroad  of  Massa- 


BALDWIN   SIX-WHEELS-CONNECTED    ENGINE,    1 842. 

chusetts,  on  a  plan  which  had  been  designed  by  that  gentleman  for 
freight  traffic.  These  machines  had  upright  boilers  and  horizontal 
cylinders,  which  worked  cranks  on  a  shaft  bearing  cog-wheels  en- 
gaging with  other  cog-wheels  on  an  intermediate  shaft.  This  latter 
shaft  had  cranks  coupled  to  four  driving-wheels  on  each  side.  These 
engines  were  constructed  to  burn  anthracite  coal.  Their  peculiarly 
uncouth  appearance  earned  for  them  the  name  of  "  crabs,"  and  they 
were  but  short-lived  in  service. 

But  to  return  to  the  progress  of  Mr.  Baldwin's  locomotive  prac- 
tice. The  geared  engine  had  not  proved  a  success.  It  was  unsat- 
isfactory^ as  well  to  its  designer  as  to  the  railroad  community.  The 
problem  of  utilizing  more  or  all  of  the  weight  of  the  engine  for  ad- 
hesion remained,  in  Mr.  Baldwin's  view,  yet  to  be  solved.  The  plan 
of  coupling  four  or  six  wheels  had  long  before  been  adopted  in 


XCVl 


HISTORY   OF   THE   STEAM-ENGINE. 


England,  but  on  the  short  curves  prevalent  on  American  railroads 
he  felt  that  something  more  was  necessary.  The  wheels  must  not 
only  be  coupled,  but  at  the  same  time  must  be  free  to  adapt  them- 
selves to  a  curve.  These  two  conditions  were  apparently  incom- 
patible, and  to  reconcile  these  inconsistencies  was  the  task  which 
Mr.  Baldwin  set  himself  to  accomplish.  He  undertook  it,  too,  at  a 
time  when  his  business  had  fallen  off  greatly  and  he  was  involved  in 
the  most  serious  financial  embarrassments.  The  problem  was  con- 
stantly before  him,  and  at  length,  during  a  sleepless  night,  its  solu- 
tion flashed  across  his  mind.     The  plan  so  long  sought  for,  and 


..^KJI^dH 


BALDWIN  FLEXIBLE-BEAM  TRUCK,   1 842 — ^^ELEVATION. 


□       Lf 


HALF  PLAN. 

which,  subsequently,  more  than  any  other  of  his  improvements  or 
inventions,  contributed  to  the  foundation  of  his  fortune,  was  his  well- 
known  six-wheels-connected  locomotive  with  the  four  front  driving- 
wheels  combined  in  a  flexible  truck.  For  this  machine  Mr.  Baldwin 
secured  a  patent,  August  25,  1842.  Its  principal  characteristic 
features  are  now  matters  of  history,  but  they  deserve  here  a  brief 
mention.  The  engine  was  on  six  wheels,  all  connected.  The  rear 
wheels  were  placed  rigidly  in  the  frames,  usually  behind  the  fire-box 
with  inside  bearings.  The  cylinders  were  inclined,  and  with  outside 
connections.  The  four  remaining  wheels  had  inside  journals  run- 
ning in  boxes  held  by  two  wide  and  deep  wrought-iron  beams,  one 


HISTORY   OF   THE   STEAM-ENGINE.  XCvil 

on  each  side.  These  beams  were  unconnected,  and  entirely  inde- 
pendent of  each  other.  The  pedestals  formed  in  them  were  bored 
out  cylindrically,  and  into  them  cylindrical  boxes,  as  patented  by 
him  in  1835,  were  fitted.  The  engine  frame  on  each  side  was 
directly  over  the  beam,  and  a  spherical  pin,  running  down  from  the 
frame,  bore  in  a  socket  in  the  beam  midway  between  the  two  axles. 
It  will  thus  be  seen  that  each  side-beam  independently  could  turn 
horizontally  or  vertically  under  the  spherical  pin,  and  the  cylindrical 
boxes  could  also  turn  in  the  pedestals.  Hence,  in  passing  a  curve, 
the  middle  pair  of  drivers  could  move  laterally  in  one  direction — say 
to  the  right — while  the  front  pair  could  move  in  the  opposite  direc- 
tion, or  to  the  left;  the  two  axles  all  the  while  remaining  parallel  to 
each  other  and  to  the  rear  driving-axle.  The  operation  of  these 
beams  was,  therefore,  like  that  of  the  parallel-ruler.  On  a  straight 
line  the  two  beams  and  the  two  axles  formed  a  rectangle ;  on  curves 
a  parallelogram,  the  angles  varying  with  the  degree  of  curvature. 
The  coupling-rods  were  made  with  cylindrical  brasses,  thus  forming 
ball-and-socket  joints,  to  enable  them  to  accommodate  themselves  to 
the  lateral  movements  of  the  wheels. 

The  first  engine  of  the  new  plan  was  finished  early  in  December, 
1842,  being  one  of  fourteen  engines  constructed  in  that  year,  and 
was  sent  to  the  Georgia  Railroad,  on  the  order  of  Mr.  J.  Edgar 
Thomson,  then  Chief  Engineer  and  Superintendent  of  that  line.  It 
weighed  twelve  tons,  and  drew,  besides  its  own  weight,  two  hundred 
and  fifty  tons  up  a  grade  of  thirty-six  feet  to  the  mile. 

Other  orders  soon  followed.  The  new  machine  was  received 
generally  with  great  favor.  The  loads  hauled  by  it  exceeded  any- 
thing so  far  known  in  American  railroad  practice,  and  sagacious 
managers  hailed  it  as  a  means  of  largely  reducing  operating  ex- 
penses. On  the  Central  Railroad,  of  Georgia,  one  of  these  twelve- 
ton  engines  drew  nineteen  eight-wheeled  cars,  with  seven  hundred 
and  fifty  bales  of  cotton,  each  bale  weighing  four  hundred  and  fifty 
pounds,  over  maximum  grades  of  thirty  feet  per  mile,  and  the 
manager  of  the  road  declared  that  it  could  readily  take  one  thousand 
bales.  On  the  Philadelphia  and  Reading  Railroad  a  similar  engine 
of  eighteen  tons  weight  drew  one  hundred  and  fifty  loaded  cars 
(total  weight  of  cars  and  lading  one  thousand  one  hundred  and 
thirty  tons)  from  Schuylkill  Haven  to  Philadelphia,  at  a  speed  of 
seven  miles  per  hour.     The  regular  load  was  one  hundred  loaded 


XCviii  HISTORY   OF   THE   STEAM-ENGINE. 

cars,  which  were  hauled  at  a  speed  of  from  twelve  to  fifteen  miles 
per  hour  on  a  level. 

But  the  flexible-beam  truck  also  enabled  Mr.  Baldwin  to  supply 
an  engine  with  four  driving-wheels  connected.  Other  builders  were 
making  engines  with  four  driving-wheels  and  a  four-wheeled  truck, 
of  the  present  American  standard  type.  To  compete  with  this  de- 
sign, Mr.  Baldwin  modified  his  six-wheels-connected  engine  by  con- 
necting only  two  out  of  the  three  pairs  of  wheels,  making  the 
forward  wheels  of  smaller  diameter  as  leading  wheels,  but  combin- 
ing them  with  the  front  driving-wheels  in  a  flexible-beam  truck. 
The  first  engine  on  this  plan  was  sent  to  the  Erie  and  Kalamazoo 
Railroad,  in  October,  1843,  ^^^  gave  great  satisfaction.  The  super- 
intendent of  the  road  was  enthusiastic  in  its  praise,  and  wrote  to 
Mr.  Baldwin  that  he  doubted  "if  anything  could  be  got  up  which 
would  answer  the  business  of  the  road  so  well."  One  was  also  sent 
to  the  Utica  and  Schenectady  Railroad  a  few  weeks  later,  of  which 
the  superintendent  remarked  that  "  it  worked  beautifully,  and  there 
were  not  wagons  enough  to  give  it  a  full  load."  In  this  plan  the 
leading  wheels  were  usually  made  thirty-six  and  the  driving-wheels 
fifty-four  inches  in  diameter. 

This  machine  of  course  came  in  competition  with  the  eight- 
wheeled  engine  having  four  driving-wheels,  and  Mr.  Baldwin 
claimed  for  his  plan  a  decided  superiority.  In  each  case  about 
two-thirds  of  the  total  weight  was  carried  on  the  four  driving- 
wheels,  and  Mr.  Baldwin  maintained  that  his  engine,  having  only 
six  instead  of  eight  wheels,  was  simpler  and  more  effective. 

At  about  this  period  Mr.  Baldwin's  attention  was  called  by  Mr. 
Levi  Bissell  to  an  "Air  Spring"  which  the  latter  had  devised,  and 
which  it  was  imagined  was  destined  to  be  a  cheap,  effective,  and 
perpetual  spring.  The  device  consisted  of  a  small  cylinder  placed 
above  the  frame  over  the  axle-box,  and  having  a  piston  fitted  air- 
tight into  it.  The  piston-rod  was  to  bear  on  the  axle-box,  and  the 
proper  quantity  of  air  was  to  be  pumped  into  the  cylinder  above  the 
piston,  and  the  cylinder  then  hermetically  closed.  The  piston  had  a 
leather  packing  which  was  to  be  kept  moist  by  some  fluid  (molasses 
was  proposed)  previously  introduced  into  the  cylinder.  Mr.  Bald- 
win at  first  proposed  to  equalize  the  weight  between  two  pairs  of 
drivers  by  connecting  two  air-springs  on  each  side  by  a  pipe,  the 
use  of  an  equalizing  beam  being  covered  by  Messrs.  Eastwick  & 


HISTORY   OF   THE   STEAM-ENGINE.  xclx 

Harrison's  patent.  The  air-springs  were  found,  however,  not  to 
work  practically,  and  were  never  applied.  It  may  be  added  that  a 
model  of  an  equalizing  air-spring  was  exhibited  by  Mr.  Joseph  Har- 
rison, Jr.,  at  the  Franklin  Institute,  in  1838  or  1839. 

With  the  introduction  of  the  new  machine,  business  began  at  once 
to  revive  and  the  tide  of  prosperity  turned  once  more  in  Mr.  Bald- 
win's favor.  Twelve  engines  were  constructed  in  1843,  all  but  four 
of  them  of  the  new  pattern;  twenty-two  engines  in  1844,  all  of  the 
new  pattern;  and  twenty-seven  in  1845.  Three  of  this  number  were 
of  the  old  type,  with  one  pair  of  driving-wheels,  but  from  that  time 
forward  the  old  pattern  with  the  single  pair  of  driving-wheels  dis- 
appeared from  the  practice  of  the  establishment,  save  occasionally 
for  exceptional  purposes. 

In  1842  the  partnership  with  Mr.  Vail  was  dissolved,  and  Mr. 
Asa  Whitney,  who  had  been  superintendent  of  the  Mohawk  and 
Hudson  Railroad,  became  a  partner  with  Mr.  Baldwin,  and  the  firm 
continued  as  Baldwin  &  Whitney  until  1846,  when  the  latter  with- 
drew to  engage  in  the  manufacture  of  car-wheels,  establishing  the 
firm  of  A.  Whitney  &  Sons,  Philadelphia. 

Mr.  Whitney  brought  to  the  firm  a  railroad  experience  and 
thorough  business  talent.  He  introduced  a  system  in  many  details 
of  the  management  of  the  business,  which  Mr.  Baldwin,  whose  mind 
was  devoted  more  exclusively  to  mechanical  subjects,  had  failed  to 
establish  or  wholly  ignored.  The  method  at  present  in  use  in  the 
establishment,  of  giving  to  each  class  of  locomotives  a  distinctive 
designation,  composed  of  a  number  and  a  letter,  originated  very 
shortly  after  Mr.  Whitney's  connection  with  the  business.  For  the 
purpose  of  representing  the  different  designs,  sheets  with  engravings 
of  locomotives  were  employed.  The  sheet  showing  the  engine  with 
one  pair  of  driving-wheels  was  marked  B;  that  with  two  pairs,  C; 
that  with  three,  D ;  and  that  with  four,  E.  Taking  its  rise  from  this 
circumstance,  it  became  customary  to  designate  as  B  engines  those 
with  one  pair  of  driving-wheels;  as  C  engines,  those  with  two  pairs; 
as  D  engines,  those  with  three  pairs;  and  as  E  engines,  those  with 
four  pairs.  Shortly  afterwards  a  number,  indicating  the  weight  in 
'  gross  tons,  was  added.  Thus,  the  12  D  engine  was  one  with  three 
pairs  of  driving-wheels,  and  weighing  twelve  tons;  the  12  C,  ail 
engine  of  same  weight,  but  with  only  four  wheels  ciDnnected.  A 
modification  of  this  method  of  designating  the  several  plans  and 
sizes  is  still  in  use.  and  is  explained  elsewhere. 


Q  HISTORY   OF   THE   STEAM-ENGINE. 

It  will  be  observed  that  the  classification  as  thus  established  began 
with  the  B  engines.  The  letter  A  was  reserved  for  an  engine 
intended  to  run  at  very  high  speeds,  and  so  designed  that  the  driv- 
ing-wheels should  make  two  revolutions  for  each  reciprocation  of 
the  pistons.  This  was  to  be  accomplished  by  means  of  gearing. 
The  general  plan  of  the  engine  was  determined  in  Mr.  Baldwin's 
mind,  but  was  never  carried  into  execution. 

The  period  under  consideration  was  marked  also  by  the  introduc- 
tion of  the  French  &  Baird  stack,  which  proved  at  once  to  be  one 
of  the  most  successful  spark-arresters  thus  far  employed,  and  which 
was  for  years  used  almost  exclusively  wherever,  as  on  the  cotton- 
carrying  railroads  of  the  South,  a  thoroughly  effective  spark-arrester 
was  required.  This  stack  was  introduced  by  Mr.  Baird,  then  a  fore- 
man in  the  works,  who  purchased  the  patent-right  of  what  had  been 
known  as  the  Grimes  stack,  and  combined  with  it  some  of  the  feat- 
ures of  the  stack  made  by  Mr.  Richard  French,  then  master 
mechanic  of  the  Germantown  Railroad,  together  with  certain  im- 
provements of  his  own.  The  cone  over  the  straight  inside  pipe  was 
made  with  volute  flanges  on  its  under  side,  which  gave  a  rotary 
motion  to  the  sparks.  Around  the  cone  was  a  casing  about  six 
inches  smaller  in  diameter  than  the  outside  stack.  Apertures  were 
cut  in  the  sides  of  this  casing,  through  which  the  sparks  in  their 
rotary  motion  were  discharged,  and  thus  fell  to  the  bottom  of  the 
space  between  the  straight  inside  pipe  and  the  outside  stack.  The 
opening  in  the  top  of  the  stack  was  fitted  with  a  series  of  V-shaped 
iron  circles  perforated  with  numerous  holes,  thus  presenting  an 
enlarged  area,  through  which  the  smoke  escaped.  The  patent-right 
for  this  stack  was  subsequently  sold  to  Messrs.  Radley  &  Hunter, 
and  its  essential  principle  is  still  used  in  the  Radley  &  Hunter  stack 
as  at  present  made. 

In  1845  Mr.  Baldwin  built  three  locomotives  for  the  Royal  Rail- 
road Committee  of  Wiirtemberg.  They  were  of  fifteen  tons  weight, 
on  six  wheels,  four  of  them  being  sixty  inches  in  diameter  and 
coupled.  The  front  driving-wheels  were  combined  by  the  flexible 
beams  into  a  truck  with  the  smaller  leading  wheels.  The  cylinders 
were  inclined  and  outside,  and  the  connecting-rods  took  hold  of  a 
half-crank  axle  back  of  the  fire-box.  It  was  specified  that  these 
engines  should  have  the  link-motion  which  had  shortly  before  been 
ijitroduced  in  England  by  the  Stephensons.     Mr.  Baldwin  accord' 


HISTORY   OF   THE   STEAM-ENGINE.  ^1 

ingly  applied  a  link  of  a  peculiar  character  to  suit  his  own  ideas  of 
the  device.  The  link  was  made  solid,  and  of  a  truncated  V-section, 
and  the  block  was  grooved  so  as  to  fit  and  slide  on  the  outside  of 
the  link. 

During  the  year  1845  another  important  feature  in  locomotive 
construction — the  cut-off  valve — was  added  to  Mr.  Baldwin's  prac- 
tice. Up  to  that  time  the  valve-motion  had  been  the  two  eccentrics, 
with  the  single  flat  hook  for  each  cylinder.  Since  1841  Mr.  Baldwin 
had  contemplated  the  addition  of  some  device  allowing  the  steam 
to  be  used  expansively,  and  he  now  added  the  "half-stroke  cut-off" 
In  this  device  the  steam-chest  was  separated  by  a  horizontal  plate 
into  an  upper  and  a  lower  compartment.  In  the  upper  compartment 
a  valve,  worked  by  a  separate  eccentric,  and  having  a  single  opening, 
admitted  steam  through  a  port  in  this  plate  to  the  lower  steam- 
chamber.  The  valve-rod  of  the  upper  valve  terminated  in  a  notch 
or  hook,  which  engaged  with  the  upper  arm  of  its  rock-shaft. 
When  thus  working,  it  acted  as  a  cut-off  at  a  fixed  part  of  the 
stroke,  determined  by  the  setting  of  the  eccentric.  This  was  usually 
at  half  the  stroke.  When  it  was  desired  to  dispense  with  the  cut-off 
and  work  steam  for  the  full  stroke,  the  hook  of  the  valve-rod  was 
lifted  from  the  pin  on  the  upper  arm  of  the  rock-shaft  by  a  lever 
worked  from  the  foot-board,  and  the  valve-rod  was  held  in  a  notched 
rest  fastened  to  the  side  of  the  boiler.  This  left  the  opening  through 
the  upper  valve  and  the  port  in  the  partition-plate  open  for  the  free 
passage  of  steam  throughout  the  whole  stroke.  The  first  application 
of  the  half-stroke  cut-off  was  made  on  the  engine  Champlain  (20  D), 
built  for  the  Philadelphia  and  Reading  Railroad  Company,  in  1845. 
It  at  once  became  the  practice  to  apply  the  cut-off  on  all  passenger 
engines,  while  the  six-  and  eight-wheels-connected  freight  engines 
were,  with  a  few  exceptions,  built  for  a  time  longer  with  the  single 
valve  admitting  steam  for  the  full  stroke. 

After  building,  during  the  years  1843,  1844,  and  1845,  ten  four- 
wheels-connected  engines  on  the  plan  above  described,  viz.,  six 
wheels  in  all,  the  leading  wheels  and  the  front  driving-wheels  being 
combined  into  a  truck  by  the  flexible  beams,  Mr.  Baldwin  finally 
adopted  the  present  design  of  four  driving-wheels  and  a  four- 
wheeled  truck.  Some  of  his  customers  who  were  favorable  to  the 
latter  plan  had  ordered  such  machines  of  other  builders,  and  Colo- 
nel Gadsden,  President  of  the  South  Carolina  Railroad  Company, 


cu 


HISTORY   OF   THE   STEAM-ENGINE. 


called  on  him  in  1845  to  build  for  that  line  some  passenger  engines 
of  this  pattern.  He  accordingly  bought  the  patent-right  for  this 
plan  of  engine  of  Mr.  H.  R.  Campbell,  and  for  the  equalizing  beams 
used  between  the  driving-wheels,  of  Messrs.  Eastwick  &  Harrison, 
and  delivered  to  the  South  Carolina  Railroad  Company,  in  Decem- 
ber, 1845,  his  first  eight-wheeled  engine  with  four  driving-wheels 
and  a  four-wheeled  truck.  This  machine  had  cylinders  thirteen 
and  three-quarters  by  eighteen,  and  driving-wheels  sixty  inches  in 
diameter,  with  the  springs  between  them  arranged  as  equalizers. 
Its  weight  was  fifteen  tons.  It  had  the  half-crank  axle,  the  cylinders 
being  inside  the  frame  but  outside  the  smoke-box.  The  inside-con- 
nected engine,  counterweighting  being  as  yet  unknown,  was  admitted 
to  be  steadier  in  running,  and  hence  more  suitable  for  passenger 


BALDWIN    EIGHT-WHEELS-CONNECTED   "c"    ENGINE,    1 846. 


service.  With  the  completion  of  the  first  eight-wheeled  "  C  "  engine 
Mr.  Baldwin's  feelings  underwent  a  revulsion  in  favor  of  this  plan, 
and  his  partiality  for  it  became  as  great  as  had  been  his  antipathy 
before.  Commenting  on  the  machine,  he  recorded  himself  as  "  more 
pleased  with  its  appearance  and  action  than  any  engine  he  had 
turned  out."  In  addition  to  the  three  engines  of  this  description 
for  the  South  Carolina  Railroad  Company,  a  duplicate  was  sent  to 
the  Camden  and  Amboy  Railroad  Company,  and  a  similar  but 
lighter  one  to  the  Wilmington  and  Baltimore  Railroad  Company, 
shortly  afterwards.  The  engine  for  the  Camden  and  Amboy  Rail- 
road Company,  and  perhaps  the  others,  had  the  half-stroke  cut-off. 

From  that  time  forward  all  of  his  four-wheels-connected  machines 
were  built  on  this  plan,  and  the  six-wheeled  "C"  engine  was  aban- 
doned, except  in  the  case  of  one  built  for  the  Philadelphia^  German- 


HISTORY   OF   THE   STEAM-ENGINE.  q\[i 

town  and  Norristown  Railroad  Company  in  1846,  and  this  was 
afterwards  rebuilt  into  a  six-wheels-connected  machine.  Three 
methods  of  carrying  out  the  general  design  were,  however,  subse- 
quently followed.  At  first  the  half-crank  was  used;  then  hori- 
zontal cylinders  inclosed  in  the  chimney-seat  and  working  a  full- 
crank  axle,  which  form  of  construction  had  been  practiced  at  the 
Lowell  Works;  and  eventually,  outside  cylinders  with  outside  con- 
nections. 

Forty-two  engines  were  completed  in  1846,  and  thirty-nine  in 
1847.  The  only  novelty  to  be  noted  among  them  was  the  engine 
M.  G.  Bright,  built  for  operating  the  inclined  plane  on  the  Madison 
and  Indianapolis  Railroad.  The  rise  of  this  incline  was  one  in 
seventeen,  from  the  bank  of  the  Ohio  river  at  Madison.  The  engine 
had  eight  wheels,  forty-two  inches  in  diameter,  connected,  and 
worked  in  the  usual  manner  by  outside  inclined  cylinders,  fifteen 
and  one-half  inches  diameter  by  twenty  inches  stroke.  A  second 
pair  of  cylinders,  seventeen  inches  in  diameter  with  eighteen  inches 
stroke  of  piston,  was  placed  vertically  over  the  boiler,  midway  be- 
tween the  furnace  and  smoke-arch.  The  connecting-rods  worked  by 
these  cylinders  connected  with  cranks  on  a  shaft  under  the  boiler. 
This  shaft  carried  a  single  cog-wheel  at  its  centre,  and  this  cog- 
wheel eng-ao-ed  with  another  of  about  twice  its  diameter  on  a  second 
shaft  adjacent  to  it  and  in  the  same  plane.  The  cog-wheel  on  this 
latter  shaft  worked  in  a  rack-rail  placed  in  the  centre  of  the  track. 
The  shaft  itself  had  its  bearings  in  the  lower  ends  of  two  vertical 
rods,  one  on  each  side  of  the  boiler,  and  these  rods  were  united 
over  the  boiler  by  a  horizontal  bar  which  was  connected  by  means 
of  a  bent  lever  and  connecting-rod  to  the  piston  worked  by  a  small 
horizontal  cylinder  placed  on  top  of  the  boiler.  By  means  of  this 
cylinder,  the  yoke  carrying  the  shaft  and  cog-wheel  could  be  de- 
pressed and  held  down  so  as  to  engage  the  cogs  with  the  rack-rail, 
or  raised  out  of  the  way  when  only  the  ordinary  driving-wheels 
were  required.  This  device  was  designed  by  Mr.  Andrew  Cathcart, 
Master  Mechanic  of  the  Madison  and  Indianapolis  Railroad.  A 
similar  machine,  the  Jolin  Brough,  for  the  same  plane,  was  built  by 
Mr.  Baldwin  in  1850.  The  incline  was  worked  with  a  rack-rail  and 
these  engines  until  it  was  finally  abandoned  and  a  line  with  easier 
gradients  substituted. 

The  use  of  iron  tubes  in  freight  engines  grew  in  favor,  and  in 


civ  HISTORY   OF   THE   STEAM-ENGINE. 

October,  1847,  Mr.  Baldwin  noted  that  he  was  fitting  his  flues  with 
copper  ends,  "  for  riveting  to  the  boiler." 

The  subject  of  burning  coal  continued  to  engage  much  attention, 
but  the  use  of  anthracite  had  not  as  yet  been  generally  successful. 
In  October,  1847,  the  Baltimore  and  Ohio  Railroad  Company  adver- 
tised for  proposals  for  four  engines  to  burn  Cumberland  coal,  and 
the  order  was  taken  and  filled  by  Mr.  Baldwin  with  four  of  his 
eight-wheels-connected  machines.  These  engines  had  a  heater  on 
top  of  the  boiler  for  heating  the  feed-water,  and  a  grate  with  a 
rocking-bar  in  the  centre,  having  fingers  on  each  side  which  inter- 
locked with  projections  on  fixed  bars,  one  in  front  and  one  behind. 
The  rocking-bar  was  operated  from  the  foot-board.  This  appears  to 
have  been  the  first  instance  of  the  use  of  a  rocking-grate  in  the 
practice  of  these  works. 

The  year  1848  showed  a  falling  off  in  business,  and  only  twenty 
engines  were  turned  out.  In  the  following  year,  however,  there  was 
a  rapid  recovery,  and  the  production  of  the  works  increased  to 
thirty,  followed  by  thirty-seven  in  1850,  and  fifty  in  185 1.  These 
engines,  with  a  few  exceptions,  were  confined  to  three  patterns,  the 
eight-wheeled  four-coupled  engine,  from  twelve  to  nineteen  tons  in 
weight,  for  passengers  and  freight,  and  the  six-  and  eight-wheels- 
connected  engine,  for  freight  exclusively,  the  six-wheeled  machine 
weighing  from  twelve  to  seventeen  tons,  and  the  eight-wheeled  from 
eighteen  to  twenty-seven  tons.  The  wheels  of  these  six-  and  eight- 
wheels-connected  machines  were  made  generally  forty-two,  with 
occasional  variations  up  to  forty-eight,  inches  in  diameter. 

The  exceptions  referred  to  in  the  practice  of  these  years  were  the 
fast  passenger  engines  built  by  Mr.  Baldwin  during  this  period. 
Early  in  1848  the  Vermont  Central  Railroad  was  approaching  com- 
pletion, and  Governor  Paine,  the  President  of  the  company,  con- 
ceived the  idea  that  the  passenger  service  on  the  road  required 
locomotives  capable  of  running  at  very  high  velocities.  Mr.  Bald- 
win at  once  undertook  to  construct  for  that  company  a  locomotive 
which  could  run  with  a  passenger  train  at  a  speed  of  sixty  miles  per 
hour.  The  work  was  begun  early  in  1848,  and  in  March  of  that 
year  Mr.  Baldwin  filed  a  caveat  for  his  design.  The  engine  was 
completed  in  1849,  and  was  named  the  Governor  Paine.  It  had  one 
pair  of  driving-wheels,  six  and  a  half  feet  in  diameter,  placed  back 
of  the  fire-box.     Another  pair  of  wheels,  but  smaller  and  uncon- 


HISTORY   OF   THE   STEAM-ENGINE. 


CV 


nected,  was  placed  directly  in  front  of  the  fire-box,  and  a  four- 
wheeled  truck  carried  the  front  of  the  engine.  The  cylinders  were 
seventeen  and  a  quarter  inches  diameter  and  twenty  inches  stroke, 
and  were  placed  horizontally  between  the  frames  and  the  boiler,  at 
about  the  middle  of  the  waist.  The  connecting-rods  took  hold  of 
"half-cranks"  inside  of  the  driving-wheels.  The  object  of  placing 
the  cylinders  at  the  middle  of  the  boiler  was  to  lessen  or  obviate  the 
lateral  motion  of  the  engine,  produced  when  the  cylinders  were 
attached  to  the  smoke-arch.  The  bearings  on  the  two  rear  axles 
were  so  contrived  that,  by  means  of  a  lever,  a  part  of  the  weight  of 
the  engine  usually  carried  on  the  wheels  in  front  of  the  fire-box 
could  be  transferred  to  the  driving-axle.  The  Governor  Paine  was 
used  for  several  years  on  the  Vermont  Central  Railroad,  and  then 


BALDWIN    FAST    PASSENGER   ENGINE,    1 848. 


rebuilt  into  a  four-coupled  machine.  During  its  career  it  was  stated 
by  the  officers  of  the  road  that  it  could  be  started  from  a  state  of 
rest  and  run  a  mile  in  forty-three  seconds.  Three  engines  on  the 
same  plan,  but  with  cylinders  fourteen  by  twenty,  and  six-feet 
driving-wheels,  the  Mifflin,  Blair,  and  Indiana,  were  also  built 
for  the  Pennsylvania  Railroad  Company  in  1849.  They  weighed 
each  about  forty-seven  thousand  pounds,  distributed  as  follows : 
eighteen  thousand  on  driving-wheels,  fourteen  thousand  on  the  pair 
of  wheels  in  front  of  the  fire-box,-  and  fifteen  thousand  on  the  truck. 
By  applying  the  lever,  the  weight  on  the  driving-wheels  could  be 
increased  to  about  twenty-four  thousand  pounds,  the  weight  on  the 
wheels  in  front  of  the  fire-box  being  correspondingly  reduced.  A 
speed  of  four  miles  in  three  minutes  is  recorded  for  them,  and  upon 


(.yj  HISTORY  OF  THE   STEAM-ENGINE. 

one  occasion  President  Taylor  was  taken  in  a  special  train  over  the 
road  by  one  of  these  machines  at  a  speed  of  sixty  miles  an  houn 
One  other  engine  of  this  pattern,  the  Susquehanna,  was  built  for 
the  Hudson  River  Railroad  Company  in  1850.  Its  cylinders  were 
fifteen  inches  diameter  by  twenty  inches  stroke,  and  driving-wheels 
six  feet  in  diameter.  All  these  engines,  however,  were  short-lived, 
and  died  young,  of  insufficient  adhesion. 

Eight  engines  with  four  driving-wheels  connected  and  half-crank 
axles  were  built  for  the  New  York  and  Erie  Railroad  Company  in 
1849,  with  seventeen  by  twenty-inch  cylinders;  one-half  of  the 
number  with  six-feet  and  the  rest  with  five-feet  driving-wheels. 
These  machines  were  among  the  last  on  which  the  half-crank  axle 
was  used.  Thereafter,  outside-connected  engines  were  constructed 
almost  exclusively. 

In  May,  1848,  Mr.  Baldwin  filed  a  caveat  for  a  four-cylinder  loco- 
motive, but  never  carried  the  design  into  execution^  The  first 
instance  of  the  use  of  steel  axles  in  the  practice  of  the  establishment 
occurred  during  the  same  year — a  set  being  placed  as  an  experiment 
under  an  engine  constructed  for  the  Pennsylvania  Railroad  Company. 
In  1850  the  old  form  of  dome  boiler,  which  had  characterized  the 
Baldwin  engine  since  1834,  was  abandoned,  and  the  wagon-top  form 
substituted. 

The  business  in  185 1  had  reached  the  full  capacity  of  the  shop, 
and  the  next  year  marked  the  completion  of  about  an  equal  number 
of  engines  (forty-nine).  Contracts  for  work  extended  a  year  ahead, 
and,  to  meet  the  demand,  the  facilities  in  the  various  departments 
were  increasec^,  and  resulted  in  the  construction  of  sixty  engines  in 
1853,  and  sixty-two  in  1854. 

At  the  beginning  of  the  latter  year,  Mr.  Matthew  Baird,  who  had 
been  connected  with  the  works  since  1 836  as  one  of  its  foremen, 
entered  into  partnership  with  Mr.  Baldwin,  and  the  style  of  the  firm 
was  made  M.  W.  Baldwin  &  Co. 

The  only  novelty  in  the  general  plan  of  engines  during  this  period 
was  the  addition  of  the  ten-wheeled  engine  to  the  patterns  of  the 
establishment.  The  success  of  Mr.  Baldwin's  engines  with  all  six 
or  eight  wheels  connected,  and  the  two  front  pairs  combined  by  the 
parallel  beams  into  a  flexible  truck,  had  been  so  marked  that  it  was 
natural  that  he  should  oppose  any  other  plan  for  freight  service. 
The  ten-wheeled  engine,  with  six  driving-wheels  connected,  had, 


HISTORY   OF   THE   STEAM-ENGINE.  CVU 

however,  now  become  a  competitor.  This  plan  of  engine  was  first 
patented  by  Septimus  Norris,  of  Philadelphia,  in  1846,  and  the 
original  design  was  apparently  to  produce  an  engine  which  should 
have  equal  tractive  povver  with  the  Baldwin  six-wheels-connected 
machine.  This  the  Norris  patent  sought  to  accomplish  by  proposing 
an  engine  with  six  driving-wheels  connected,  and  so  disposed  as  to 
carry  substantially  the  whole  weight,  the  forward  driving-wheels 
being  in  advance  of  the  centre  of  gravity  of  the  engine,  and  the  truck 
only  serving  as  a  guide,  the  front  of  the  engine  being  connected 
with  it  by  a  pivot-pin,  but  without  a  bearing  on  the  centre-plate. 
Mr.  Norris's  first  engine  on  this  plan  was  tried  in  April,  1847,  and 
was  found  not  to  pass  curves  so  readily  as  was  expected.  As  the 
truck  carried  little  or  no  weight,  it  would  not  keep  the  track.  The 
New  York  and  Erie  Railroad  Company,  of  which  John  Brandt 
was  then  Master  Mechanic,  shortly  afterwards  adopted  the  ten- 
wheeled  engine,  modified  in  plan  so  as  to  carry  a  part  of  the  weight 
on  the  truck.  Mr.  Baldwin  filled  an  order  for  this  company,  in 
1850,  of  four  eight-wheels-connected  engines,  and  in  making  the 
contract  he  agreed  to  substitute  a  truck  for  the  front  pair  of  wheels 
if  desired  after  trial.     This,  however,  he  was  not  called  upon  to  do. 

In  February,  1852,  Mr.  J.  Edgar  Thomson,  President  of  the  Penn- 
sylvania Railroad  Company,  invited  proposals  for  a  number  of 
freight  locomotives  of  fifty-six  thousand  pounds  weight  each.  They 
were  to  be  adapted  to  burn  bituminous  coal,  and  to  have  six  wheels 
connected  and  a  truck  in  front,  which  might  be  either  of  two  or  four 
wheels.  Mr.  Baldwin  secured  the  contract,  and  built  twelve  engines 
of  the  prescribed  dimensions,  viz.,  cylinders  eighteen  by  twenty-two ; 
driving-wheels  forty-four  inches  in  diameter,  with  chilled  tires. 
Several  of  these  engines  were  constructed  with  a  single  pair  of  truck- 
wheels  in  front  of  the  driving-wheels,  but  back  of  the  cylinders.  It 
was  found,  however,  after  the  engines  were  put  in  service,  that  the 
two  truck-wheels  carried  eighteen  thousand  or  nineteen  thousand 
pounds,  and  this  was  objected  to  by  the  company  as  too  great  a 
weight  to  be  carried  on  a  single  pair  of  wheels.  On  the  rest  of  the 
engines  of  the  order,  therefore,  a  four-wheeled  truck  in  front  was 
employed. 

The  ten-wheeled  engine  thereafter  assumed  a  place  in  the  Baldwin 
classification.  In  1855-56,  two  of  twenty-seven  tons  weight,  nine- 
teen by  twenty-two   cylinders,  forty-eight   inches    driving-wheels, 


CVJii  HISTORY   OF   THE   STEAM-ENGINE. 

were  built  for  the  Portage  Railroad,  and  three  for  the  Pennsylvania 
Railroad.  In  1855,  '56,  and  '57,  fourteen  of  the  same  dimensions 
were  built  for  the  Cleveland  and  Pittsburg  Railroad ;  four  for  the 
Pittsburg,  Fort  Wayne  and  Chicago  Railroad ;  and  one  for  the 
Marietta  and  Cincinnati  Railroad.  In  1858  and  '59,  one  was  con- 
structed for  the  South  Carolina  Railroad,  of  the  same  size,  and  six 
lighter  ten  wheelers,  with  cylinders  fifteen  and  a  half  by  twenty-two, 
and  four-feet  driving-wheels,  and  two  with  cylinders  sixteen  by 
twenty-two,  and  four-feet  driving-wheels,  were  sent  out  to  railroads 
in  Cuba. 

It  was  some  years — not  until  after  i860,  however — before  this 
pattern  of  engine  wholly  superseded  in  Mr.  Baldwin's  practice  the 
old  plan  of  freight  engine  on  six  or  eight  wheels,  all  connected. 

On  three  locomotives — the  Clinton,  Athens,  and  Sparta — 
completed  for  the  Central  Railroad  of  Georgia  in  July,  1852,  the 
driving-boxes  were  made  with  a  slot  or  cavity  in  the  line  of  the 
vertical  bearing  on  the  journal.  The  object  was  to  produce  a  more 
uniform  distribution  of  the  wear  over  the  entire  surface  of  the  bear- 
ing. This  was  the  first  instance  in  which  this  device,  which  has 
since  come  into  general  use,  was  employed  in  the  Works,  and  the 
boxes  were  so  made  by  direction  of  Mr.  Charles  Whiting,  then 
Master  Mechanic  of  the  Central  Railroad  of  Georgia.  He  subse- 
quently informed  Mr.  Baldwin  that  this  method  of  fitting  up  driving- 
boxes  had  been  in  use  on  the  road  for  several  years  previous  to  his 
connection  with  the  company.  As  this  device  was  subsequently 
made  the  subject  of  a  patent  by  Mr.  David  Matthew,  these  facts  may 
not  be  without  interest. 

In  1853,  Mr.  Charles  Ellet,  Chief  Engineer  of  the  Virginia  Central 
Railroad,  laid  a  temporary  track  across  the  Blue  Ridge,  at  Rock 
Fish  Gap,  for  use  during  the  construction  of  a  tunnel  through  the 
mountain.  This  track  was  twelve  thousand  five  hundred  feet  in 
length  on  the  eastern  slope,  ascending  in  that  distance  six  hundred 
and  ten  feet,  or  at  the  average  rate  of  one  in  twenty  and  a  half  feet. 
The  maximum  grade  was  calculated  for  two  hundred  and  ninety-six 
feet  per  mile,  and  prevailed  for  half  a  mile.  It  was  found,  however, 
in  fact,  that  the  grade  in  places  exceeded  three  hundred  feet  per 
mile.  The  shortest  radius  of  curvature  was  two  hundred  and  thirty- 
eight  feet.  On  the  western  slope,  which  was  ten  thousand  six  hun- 
dred and  fifty  feet  in  length,  the  maximum  grade  was  two  hundred 


HISTORY   OF   THE   STEAM-ENGINE.  CIX 

and  eighty  feet  per  mile,  and  the  ruHng  radius  of  curvature  three  hun- 
dred feet.  This  track  was  worked  by  two  of  the  Baldwin  six-wheels- 
connected  flexible-beam  truck  locomotives  constructed  in  1853-54. 

But  the  period  now  under  consideration  was  marked  by  another, 
and  a  most  important,  step  in  the  progress  of  American  locomotive 
practice.  We  refer  to  the  introduction  of  the  link-motion.  Al- 
though this  device  was  first  employed  by  William  T.  James,  of  New 
York,  in  1832,  and  eleven  years  later  by  the  Stephensons,  in  Eng- 
land, and  was  by  them  applied  thenceforward  on  their  engines,  it 
was  not  until  1 849  that  it  was  adopted  in  this  country.  In  that  year 
Mr.  Thomas  Rogers,  of  the  Rogers  Locomotive  and  Machine  Com- 
pany, introduced  it  in  his  practice.  Other  builders,  however,  strenu- 
ously resisted  the  innovation,  and  none  more  so  than  Mr.  Baldwin. 
The  theoretical  objections  which  confessedly  apply  to  the  device, 
but  which  practically  have  been  proved  to  be  unimportant,  were 
urged  from  the  first  by  Mr.  Baldwin  as  arguments  against  its  use. 
The  strong  claim  of  the  advocates  of  the  link-motion,  that  it  gave  a 
means  of  cutting  off  steam  at  any  point  of  the  stroke,  could  not  be 
gainsaid,  and  this  was  admitted  to  be  a  consideration  of  the  first 
importance.  This  very  circumstance  undoubtedly  turned  Mr.  Bald- 
win's attention  to  the  subject  of  methods  for  cutting  off  steam,  and 
one  of  the  first  results  was  his  "Variable  Cut-off,"  patented  April 
27,  1852.  This  device  consisted  of  two  valves,  the  upper  sliding 
upon  the  lower,  and  worked  by  an  eccentric  and  rock-shaft  in  the 
usual  manner.  The  lower  valve  fitted  steam-tight  to  the  sides  of  the 
steam-chest  and  the  under  surface  of  the  upper  valve.  When  the 
piston  reached  each  end  of  its  stroke,  the  full  pressure  of  steam  from 
the  boiler  was  admitted  around  the  upper  valve,  and  transferred  the 
lower  valve  instantaneously  from  one  end  of  the  steam-chest  to  the 
other.  The  openings  through  the  two  valves  were  so  arranged  that 
steam  was  admitted  to  the  cylinder  only  for  a  part  of  the  stroke. 
The  effect  was,  therefore,  to  cut  off  steam  at  a  given  point,  and  to 
open  the  induction  and  exhaust  ports  substantially  at  the  same 
instant  and  to  their  full  extent.  The  exhaust  port,  in  addition, 
remained  fully  open  while  the  induction  port  was  gradually  closing, 
and  after  it  had  entirely  closed.  Although  this  device  was  never  put 
in  use,  it  may  be  noted  in  passing  that  it  contained  substantially  the 
principle  of  the  steam-pump,  as  since  patented  and  constructed. 

Early  in  1853  Mr.  Baldwin  abandoned  the   half-stroke  cut-off, 


ex 


HISTORY   OF  THE   STEAM-ENGINE. 


previously  ^described,  and  which  he  had  been  using  since  1845,  and 
adopted  the  variable  cut-off,  which  was  already  employed  by  other 
builders.  One  of  his  letters,  written  in  January,  1853,  states  his 
position,  as  follows : 

"  I  shall  put  on  an  improvement  in  the  shape  of  a  variable  cut-off,  which  can  be 
operated  by  the  engineer  while  the  machine  is  running,  and  which  will  cut  off  anywhere 
from  six  to  twelve  inches,  according  to  the  load  and  amount  of  steam  wanted,  and  this 
without  the  link-motion,  which  I  could  never  be  entirely  satisfied  with.  I  still  have  the 
independent  cut-off,  and  the  additional  machinery  to  make  it  variable  will  be  simple  and 
not  liable  to  be  deranged." 

This  form  of  cutoff  was  a  separate  valve,  sliding  on  a  partition 
plate  betv/een  it  and  the  main  steam-valve,  and  worked  by  an  inde- 
pendent eccentric  and  rock-shaft.  The  upper  arm  of  the  rock-shaft 
was  curved  so  as  to  form  a  radius-arm,  on  which  a  sliding-block, 
forming  the  termination  of  the  upper  valve-rod,  could  be  adjusted 
and  held  at  varying  distances  from  the  axis,  thus  producing  a  vari- 
able travel  of  the  upper  valve.  This  device  did  not  give  an  abso- 
lutely perfect  cut-off,  as  it  was  not  operative  in  backward  gear,  but 
when  running  forward  it  would  cut  off  with  great  accuracy  at  any 
point  of  the  stroke,  was  quick  in  its  movement,  and  economical  in 
the  consumption  of  fuel. 

After  a  short  experience  with  this  arrangement  of  the  cut-off,  the 
partition  plate  was  omitted,  and  the  upper  valve  was  made  to  slide 
directly  on  the  lower.  This  was  eventually  found  objectionable, 
however,  as  the  lower  valve  would  soon  cut  a  hollow  in  the  valve- 
face.  Several  unsuccessful  attempts  were  made  to  remedy  this  defect 
by  making  the  lower  valve  of  brass,  with  long  bearings,  and  making 
the  valve-face  of  the  cylinder  of  hardened  steel;  finally,  however, 
the  plan  of  one  valve  on  the  other  was  abandoned  and  a  recourse 
was  again  had  to  an  interposed  partition  plate,  as  in  the  original 
half-stroke  cut-off 

Mr.  JBaldwin  did  not  adopt  this  form  of  cut-off  without  some 
modification  of  his  own,  and  the  modification  in  this  instance  con- 
sisted of  a  peculiar  device,  patented  September  13,  1853,  for  raising 
and  lowering  the  block  on  the  radius-arm.  A  quadrant  was  placed 
so  that  its  circumference  bore  nearly  against  a  curved  arm  projecting 
down  from  the  sliding-block,  and  which  curved  in  the  reverse  direc- 
tion from  the  quadrant.  Two  steel  straps  side  by  side  were  inter- 
posed between  the  quadrant  and  this  curved  arm.    One  of  the  straps 


HISTORY   OF   THE   STEAM-ENGINE. 


CXI 


was  connected  to  the  lower  end  of  the  quadrant  and  the  upper  end 
of  the  curved  arm;  the  other  to  the  upper  end  of  the  quadrant  aad 
the  lower  end  of  the  curved  arm.  The  effect  was  the  same  as  if  the 
quadrant  and  arm  geared  into  each  other  in  any  position  by  teeth, 
and  theoretically  the  block  was  kept  steady  in  whatever  position 


VARIABLE   CUT-OFF   ADJUSTMENT. 

placed  on  the  radius-arm  of  the  rock-shaft.  This  was  the  object 
sought  to  be  accomplished,  and  was  stated  in  the  specification  of  the 
patent  as  follows : 

"  The  principle  of  varying  the  cut-off  by  means  of  a  vibrating  arm  and  sliding  pivot- 
block  has  long  been  known,  but  the  contrivances  for  changing  the  position  of  the  block 
upon  the  arm  have  been  very  defective.  The  radius  of  motion  of  the  link  by  which  the 
sliding-block  is  changed  on  the  arm,  and  the  radius  of  motion  of  that  part  of  the  vibrating 
arm  on  which  the  block  is  placed,  have,  in  this  kind  of  valve-gear,  as  heretofore  con- 
structed, been  different,  which  produced  a  continual  rubbing  of  the  sliding-block  upon 
the  arm  while  the  arm  is  vibrating;  and  as  the  block  for  the  greater  part  of  the  time 
occupies  one  position  on  the  arm,  and  only  has  to  be  moved  toward  either  extremity 
occasionally,  that  part  of  the  arm  on  which  the  block  is  most  used  soon  becomes  so  worn 
that  the  block  is  loose,  and  jars." 

This  method  of  varying  the  cut-off  was  first  applied  on  the 
engine  Belle,  delivered  to  the  Pennsylvania  Railroad  Company, 
December  6,  1854,  and  thereafter  was  for  some  time  employed  by 
Mr.  Baldwin.  It  was  found,  however,  in  practice  that  the  steel 
straps  would  stretch  sufficiently  to  allow  them  to  buckle  and  break, 
and  hence  they  were  soon  abandoned,  and  chains  substituted  be- 
tween the  quadrant  and  curved  arm  of  the  sliding-block.  These 
chains  in  turn  proved  little  better,  as  they  lengthened,  allowing  lost 
motion,  or  broke  altogether,  so  that  eventually  the  quadrant  was 
wholly  abandoned,  and  recourse  was  finally  had  to  the  lever  and 
link  for  raising  and  lowering  the  sliding-block.  As  thus  arranged, 
the  cut-off  was  substantially  what  was  known  as  the  "  Cuyahoga  Cut- 


Cxii  HISTORY   OF   THE   STEAM-ENGINE. 

ofif,"  as  introduced  by  Mr.  Ethan  Rogers,  of  the  Cuyahoga  Works, 
Cleveland,  Ohio,  except  that  Mr.  Baldwin  used  a  partition  plate  be- 
tween the  upper  and  the  lower  valve. 

But  while  Mr.  Baldwin,  in  common  with  many  other  builders, 
was  thus  resolutely  opposing  the  link-motion,  it  was  nevertheless 
rapidly  gaining  favor  with  railroad  managers.  Engineers  and  mas- 
ter mechanics  were  everywhere  learning  to  admire  its  simplicity, 
and  were  manifesting  an  enthusiastic  preference  for  engines  so  con- 
structed. At  length,  therefore,  he  was  forced  to  succumb :  and  the 
link  was  applied  to  the  Pennsylvania,  one  of  two  engines  completed 
for  the  Central  Railroad  of  Georgia,  in  February,  1854.  The  other 
engine  of  the  order,  the  Nezv  Hampshire,  had  the  variable  cut-off, 
and  Mr.  Baldwin,  while  yielding  to  the  demand  in  the  former  en- 
gine, was  undoubtedly  sanguine  that  the  working  of  the  latter  would 
demonstrate  the  inferiority  of  the  new  device.  In  this,  however,  he 
was  disappointed,  for  in  the  following  year  the  same  company 
ordered  three  more  engines,  on  which  they  specified  the  link-motion. 
In  1856  seventeen  engines  for  nine  different  companies  had  this 
form  of  valve  gear,  and  its  use  was  thus  incorporated  in  his  practice. 
It  was  not,  however,  until  1857  that  he  was  induced  to  adopt  it 
exclusively. 

February  14,  1854,  Mr.  Baldwin  and  Mr.  David  Clark,  Master 
Mechanic  of  the  Mine  Hill  Railroad,  took  out  conjointly  a  patent 
for  a  feed-water  heater,  placed  at  the  base  of  a  locomotive  chimney, 
and  consisting  of  one  large  vertical  flue,  surrounded  by  a  number 
of  smaller  ones.  The  exhaust  steam  was  discharged  from  the  noz- 
zles through  the  large  central  flue,  creating  a  draft  of  the  products 
of  combustion  through  the  smaller  surrounding  flues.  The  pumps 
forced  the  feed-water  into  the  chamber  around  these  flues,  whence 
it  passed  to  the  boiler  by  a  pipe  from  the  back  of  the  stack.  This 
heater  was  applied  on  several  engines  for  the  Mine  Hill  Railroad, 
and  on  a  few  for  other  roads ;  but  its  use  was  exceptional,  and 
lasted  only  for  a  year  or  two. 

In  December  of  the  same  year  Mr.  Baldwin  filed  a  caveat  for  a 
variable  exhaust,  operated  automatically,  by  the  pressure  of  steam, 
so  as  to  close  when  the  pressure  was  lowest  in  the  boiler,  and  open 
with  the  increase  of  pressure.     The  device  was  never  put  in  service. 

The  use  of  coal,  both  bituminous  and  anthracite,  as  a  fuel  for 
locomotives,  had  by   this  time  become  a  practical  success.     The 


HISTORY   OF   THE   STEAM-ENGINE.  cxiil 

economical  combustion  of  bituminous  coal,  however,  engaged  con- 
siderable attention.  It  was  felt  that  much  remained  to  be  accom- 
plished in  consuming  the  smoke  and  deriving  the  maximum  of  useful 
effect  from  the  fuel.  Mr.  Baird,  who  was  now  associated  with  Mr. 
Baldwin  in  the  management  of  the  business,  made  this  matter  a  sub- 
ject of  careful  study  and  investigation.  An  experiment  was  con 
ducted  under  his  direction,  by  placing  a  sheet-iron  deflector  in  the 
fire-box  of  an  engine  on  the  Germantown  and  Norristown  Railroad. 
The  success  of  the  trial  was  such  as  to  show  conclusively  that  a 
more  complete  combustion  resulted.  As,  however,  a  deflector 
formed  by  a  single  plate  of  iron  would  soon  be  destroyed  by  the 
action  of  the  fire,  Mr.  Baird  proposed  to  use  a  water- leg  projecting 
upward  and  backward  from  the  front  of  the  fire-box  under  the  flues. 
Drawings  and  a  model  of  the  device  were  prepared,  with  a  view  of 
patenting  it,  but  subsequently  the  intention  was  abandoned,  Mr. 
Baird  concluding  that  a  fire-brick  arch  as  a  deflector  to  accomplish 
the  same  object  was  preferable.  This  was  accordingly  tried  on  two 
locomotives  built  for  the  Pennsylvania  Railroad  Company  in  1854, 
and  was  found  so  valuable  an  appliance  that  its  use  was  at  once 
established,  and  it  was  put  on  a  number  of  engines  built  for  railroads 
in  Cuba  and  elsewhere.  For  several  years  the  fire-bricks  were  sup- 
ported on  side  plugs;  but  in  1858,  in  the  Media,  built  for  the  West 
Chester  and  Philadelphia  Railroad  Company,  water-pipes  extending 
from  the  crown  obliquely  downward  and  curving  to  the  sides  of  the 
fire-box  at  the  bottom  were  successfully  used  for  the  purpose. 

The  adoption  of  the  link-motion  may  be  regarded  as  the  dividing 
line  between  the  present  and  the  early  and  transitional  stage  of 
locomotive  practice.  Changes  since  that  event  have  been  principally 
in  matters  of  detail,  but  it  is  the  gradual  perfection  of  these  details 
which  has  made  the  locomotive  the  symmetrical,  efiicient,  and  wonder- 
fully complete  piece  of  mechanism  it  is  to-day.  In  perfecting  these 
minutiae,  the  Baldwin  Locomotive  works  has  borne  its  part,  and  it 
only  remains  to  state  briefly  its  contributions  in  this  direction. 

The  production  of  the  establishment  during  the  six  years  from 
1855  to  i860,  inclusive,  was  as  follows;  forty-seven  engines  in 
1855;  fifty-nine  in  1856;  sixty-six  in  1857;  thirty-three  in  1858; 
seventy  in  1859;  and  eighty-three  in  i860.  The  greater  number 
of  these  were  of  the  ordinary  type,  four  wheels  coupled,  and  a  four- 
wheeled  truck,  and  varying  in  weight  from  fifteen  ton  engines,  with 


j^xiv  HISTORY   OF   THE   STEAM-ENGINE. 

cylinders  twelve  by  twenty-two,  to  twenty-seven  ton  engines,  with 
cylinders  sixteen  by  twenty-four.  A  few  ten-wheeled  engines  were 
built,  as  has  been  previously  noted,  and  the  remainder  were  the 
Baldwin  flexible-truck  six-  and  eight-wheels- connected  engines. 
The  demand  for  these,  however,  was  now  rapidly  falling  off,  the 
ten-wheeled  and  heavy  "  C  "  engines  taking  their  place,  and  by  1859 
they  ceased  to  be  built,  save  in  exceptional  cases,  as  for  some  foreign 
roads,  from  which  orders  for  this  pattern  were  still  occasionally 
received. 

A  few  novelties  characterizing  the  engines  of  this  period  may  be 
mentioned.  Several  engines  built  in  1855  had  cross-flues  placed  in 
the  fire-box,  under  the  crown,  in  order  to  increase  the  heating  sur- 
face. This  feature,  however,  was  found  impracticable,  and  was  soon 
abandoned.  The  intense  heat  to  which  the  flues  were  exposed  con- 
verted the  water  contained  in  them  into  highly  super-heated  steam, 
which  would  force  its  way  out  through  the  water  around  the  fire-box 
with  violent  ebullitions.  Four  engines  were  built  for  the  Pennsyl- 
vania Railroad  Company,  in  1856-57,  with  straight  boilers  and  two 
domes.  The  Delano  grate,  by  means  of  which  the  coal  was  forced 
into  the  fire-box  from  below,  was  applied  on  four  ten-wheeled  en- 
gines for  the  Cleveland  and  Pittsburg  Railroad  in  1857.  In  1859 
several  ensfines  were  built  with  the  form  of  boiler  introduced  on  the 
Cumberland  Valley  Railroad  in  185 1  by  Mr.  A.  F.  Smith,  and  which 
consisted  of  a  combustion-chamber  in  the  waist  of  the  boiler,  next 
the  fire-box.  This  form  of  boiler  was  for  some  years  thereafter 
largely  used  in  engines  for  soft  coal.  It  was  at  first  constructed 
with  the  "  water-leg,"  which  was  a  vertical  water-space,  connecting 
the  top  and  bottom  sheets  of  the  combustion-chamber,  but  even- 
tually this  feature  was  omitted,  and  an  unobstructed  combustion- 
chamber  employed.  Several  engines  were  built  for  the  Philadelphia, 
Wilmington  and  Baltimore  Railroad  Company  in  1859,  and  there- 
after, with  the  Dimpfel  boiler,  in  which  the  tubes  contain  water,  and 
starting  downward  from  the  crown-sheet,  are  curved  to  the  horizontal, 
and  terminate  in  a  narrow  water-space  next  the  smoke-box.  The 
whole  waist  of  the  boiler,  therefore,  forms  a  combustion  chamber, 
and  the  heat  and  gases,  after  passing  for  their  whole  length  along  and 
around  the  tubes,  emerge  into  the  lower  part  of  the  smoke-box. 

In  i860  an  engine  was  built  for  the  Mine  Hill  Railroad,  with  a 
boiler  of  a  peculiar  form.     The  top  sheets  sloped  upward  from  both 


HISTORY   OF   THE    STEAM-ENGINE.  qxV 

ends  towards  the  centre,  thus  making  a  raised  part  or  hump  in  the 
centre.  The  engine  was  designed  to  work  on  heavy  grades,  and 
the  object  sought  by  Mr.  Wilder,  the  Superintendent  of  the  Mine 
Hill  Railroad,  was  to  have  the  water  always  at  the  same  height  in 
the  space  from  which  steam  was  drawn,  whether  going  up  or  down 
grade. 

All  these  experiments  are  indicative  of  the  interest  then  prevail- 
ing upon  the  subject  of  coal-burning.  The  result  of  experience  and 
study  had  meantime  satisfied  Mr.  Baldwin  that  to  burn  soft  coal 
successfully  required  no  peculiar  devices ;  that  the  ordinary  form  of 
boiler,  with  plain  fire-box,  was  right,  with  perhaps  the  addition  of  a 
fire-brick  deflector ;  and  that  the  secret  of  the  economical  and  suc- 
cessful use  of  coal  was  in  the  mode  of  firing,  rather  than  in  a  differ- 
ent form  of  furnace. 

The  year  i86i  witnessed  a  marked  falling  off  in  the  production. 
The  breaking  out  of  the  civil  war  at  first  unsettled  business,  and  by 
many  it  was  thought  that  railroad  traffic  would  be  so  largely  re- 
duced that  the  demand  for  locomotives  must  cease  altogether.  A 
large  number  of  hands  were  discharged  from  the  works,  and  only 
forty  locomotives  were  turned  out  during  the  year.  It  was  even 
seriously  contemplated  to  turn  the  resources  of  the  establishment  to 
the  manufacture  of  shot  and  shell,  and  other  munitions  of  war,  the 
belief  being  entertained  that  the  building  of  locomotives  would  have 
to  be  altogether  suspended.  So  far,  however,  was  this  from  being 
the  case,  that,  after  the  first  excitement  had  subsided,  it  was  found 
that  the  demand  for  transportation  by  the  general  government,  and 
by  the  branches  of  trade  and  production  stimulated  by  the  war,  was 
likely  to  tax  the  carrying  capacity  of  the  principal  Northern  railroads 
to  the  fullest  extent.  The  government  itself  became  a  large  pur- 
chaser of  locomotives,  and  it  is  noticeable,  as  indicating  the  increase 
of  travel  and  freight  transportation,  that  heavier  machines  than  had 
ever  before  been  built  became  the  rule.  Seventy-five  engines  were 
sent  from  the  works  in  1862  ;  ninety-six  in  1863 ;  one  hundred  and 
thirty  in  1864;  and  one  hundred  and  fifteen  in  1865.  During  two 
years  of  this  period,  from  May,  1862,  to  June,  1864,  thirty-three  en- 
gines were  built  for  the  United  States  Military  Railroads.  The  de- 
mand from  the  various  coal-carrying  roads  in  Pennsylvania  and 
vicinity  was  particularly  active,  and  large  numbers  of  ten-wheeled 
engines,  and   of  the  heaviest  eight-wheeled  four-coupled  engines, 


j^yj  HISTORY  OF  TpE   STEAM-ENGINE. 

were  built.  Of  the  latter  class,  the  majority  were  with  fifteen-  and 
sixteen-inch  cylinders,  and  of  the  former,  seventeen-  and  eighteen- 
inch  cylinders. 

The  introduction  of  several  important  features  in  construction 
marks  this  period.  Early  in  i86i,  four  eighteen-inch  cylinder 
freight  locomotives,  with  six  coupled  wheels,  fifty-two  inches  in  di- 
ameter, and  a  Bissell  pony-truck  with  radius-bar  in  front,  were  sent 
to  the  Louisville  and  Nashville  Railroad  Company.  This  was  the 
first  instance  of  the  use  of  the  Bissell  truck  in  the  Baldwin  Works. 
These  engines,  however,  were  not  of  the  regular  Mogul  type,  as 
they  were  only  modifications  of  the  ten-wheeler,  the  drivers  retaining 
the  same  position,  well  back,  and  a  pair  of  pony-wheels  on  the  Bis- 
sell plan  taking  the  place  of  the  ordinary  four-wheeled  truck.  Other 
engines  of  the  same  pattern,  but  with  eighteen  and  one-half  inch 
cylinders,  were  built  in  1862-63,  for  the  same  company,  and  for  the 
Dom  Pedro  II.  Railway  of  Brazil. 

The  introduction  of  steel  in  locomotive-construction  was  a  dis- 
tinguishing feature  of  the  period.  Steel  tires  were  first  used  in  the 
works  in  1862,  on  some  engines  for  the  Dom  Pedro  II.  Railway  of 
South  America.  Their  general  adoption  on  American  Railroads 
followed  slowly.  No  tires  of  this  material  were  then  made  in  this 
country,  and  it  was  objected  to  their  use  that,  as  it  took  from  sixty 
to  ninety  days  to  import  them,  an  engine,  in  case  of  a  breakage  of 
one  of  its  tires,  might  be  laid  up  useless  for  several  months.  To 
obviate  this  objection  M.  W.  Baldwin  &  Co.  imported  five  hundred 
steel  tires,  most  of  which  were  kept  in  stock,  from  which  to  fill 
orders.  The  steel  tires  as  first  used  in  1862  on  the  locomotives 
for  the  Dom  Pedro  Segundo  Railway  were  made  with  a  "  shoulder  " 
at  one  edge  of  the  internal  periphery,  and  were  shrunk  on  the  wheel- 
centres. 

Steel  fire-boxes  were  first  built  for  some  engines  for  the  Pennsyl- 
vania Railroad  Company  in  1861.  English  steel  of  a  high  temper 
was  used,  and  at  the  first  attempt  the  fire-boxes  cracked  in  fitting 
them  in  the  boilers,  and  it  became  necessary  to  take  them  out  and 
substitute  copper.  American  homogeneous  cast-steel  was  then 
tried  on  engines  231  and  232,  completed  for  the  Pennsylvania  Rail- 
road in  January,  1862,  and  it  was  found  to  work  successfully.  The 
fire-boxes  of  nearly  all  engines  thereafter  built  for  that  road  were 
of  this  material,  and  in  1 866  its  use  for  the  purpose  became  general. 


HISTORY   OF   THE   STEAM-ENGINE. 


CXVll 


It  may  be  added  that  while  all  steel  sheets  for  fire-boxes  or  boilers 
are  required  to  be  thoroughly  annealed  before  delivery,  those  which 
are  flanged  or  worked  in  the  process  of  boiler  construction  are  a 
second  time  annealed  before  riveting. 

Another  feature  of  construction  gradually  adopted  was  the  placing 
of  the  cylinders  horizontally.  This  was  first  done  in  the  case  of  an 
outside-connected  engine,  the  Ocnmlgee,  which  was  sent  to  the 
Southwestern  Railroad  Company  of 
Georgia,  in  January,  1858.  This  engine 
had  a  square  smoke-box,  and  the  cylin- 
ders were  bolted  horizontally  to  its  sides. 
The  plan  of  casting  the  cylinder  and  half- 
saddle  in  one  piece  and  fitting  it  to  the 
round  smoke-box  was  introduced  by  Mr. 
Baldwin,  and  grew  naturally  out  of  his 
original  method  of  construction.  Mr. 
Baldwin  was  the  first  American  builder 
to  use  an  outside  cylinder,  and  he  made 
it  for  his  early  engines  with  a  circular 
flange  cast  to  it,  by  which  it  could  be 
bolted  to  the  boiler.  The  cylinders  were 
gradually  brought  lower,  and  at  a  less 
angle,  and  the  flanges  prolonged  and  en- 
larged. In  1852  three  six-wheels-con- 
nected engines,  for  the  Mine  Hill  Railroad  Company,  were  built  with 
the  cylinder  flanges  brought  around  under  the  smoke-box  until  they 
nearly  met,  the  space  between  them  being  filled  with  a  spark -box. 
This  was  practically  equivalent  to  making  the  cylinder  and  half- 
saddle  in  one  casting.  Subsequently,  on  other  engines  on  which  the 
spark -box  was  not  used,  the  half-saddles  were  cast  so  as  almost  to 
meet  under  the  smoke-box,  and,  after  the  cylinders  were  adjusted  in 
position,  wedges  were  fitted  in  the  interstices  and  the  saddles  bolted 
together.  It  was  finally  discovered  that  the  faces  of  the  two  half- 
saddles  might  be  planed  and  finished  so  that  they  could  be  bolted 
together  and  bring  the  cylinders  accurately  in  position,  thus  avoiding 
the  troublesome  and  tedious  job  of  adjusting  them  by  chipping  and 
fitting  to  the  boiler  and  frames.  With  this  method  of  construction 
the  cylinders  were  placed  at  a  less  and  less  angle,  until  at  length  the 
truck-wheels  were  spread  sufficiently,  on  all  new  or  modified  classes 


HORIZONTAL    CYLINDERS. 


QXy'm  HISTORY   OF   THE   STEAM-ENGINE. 

of  locomotives  in  the  Baldwin  list,  to  admit  of  the  cylinders  being 
hung  horizontally,  as  is  the  present  almost  universal  American  prac- 
tice. By  the  year  1865  horizontal  cylinders  were  made  in  all  cases 
where  the  patterns  would  allow  it.  The  advantages  of  this  arrange- 
ment are  manifestly  in  the  interest  of  simplicity  and  economy,  as  the 
cylinders  are  thus  rights  or  lefts,  indiscriminately,  and  a  single  pat- 
tern answers  for  either  side. 

A  distinguishing  feature  in  the  method  of  construction  which 
characterizes  these  works  is  the  extensive  use  of  a  system  of  standard 
gauges  and  templets,  to  which  all  work  admitting  of  this  process  is 
required  to  be  made.  The  importance  of  this  arrangement,  in  se- 
curing absolute  uniformity  of  essential  parts  in  all  engines  of  the 
same  class,  is  manifest,  and  with  the  increased  production  since  1861 
it  became  a  necessity  as  well  as  a  decided  advantage. 

Thus  had  been  developed  and  perfected  the  various  essential 
details  of  existing  locomotive  practice  when  Mr.  Baldwin  died,  Sep- 
tember 7,  1866.  He  had  been  permitted,  in  a  life  of  unusual  activity 
and  energy,  to  witness  the  rise  and  wonderful  increase  of  a  material 
interest  which  had  become  the  distinguishing  feature  of  the  century. 
He  had  done  much,  by  his  own  mechanical  skill  and  inventive  genius, 
to  contribute  to  the  development  of  that  interest.  His  name  was  as 
"  familiar  as  household  words  "  wherever  on  the  American  continent 
the  locomotive  had  penetrated. 

To  do  right,  absolutely  and  unreservedly,  in  all  his  relations 
with  men,  was  an  instinctive  rule  of  his  nature.  His  heroic  struggle 
to  meet  every  dollar  of  his  liabilities,  principal  and  interest,  after  his 
failure,  consequent  upon  the  general  financial  crash  in  1837,  con- 
stitutes a  chapter  of  personal  self-denial  and  determined  effort  which 
is  seldom  paralleled  in  the  annals  of  commercial  experience.  When 
most  men  would  have  felt  that  an  equitable  compromise  with  credi- 
tors was  all  that  could  be  demanded  in  view  of  the  general  financial 
embarrassment,  Mr.  Baldwin  insisted  upon  paying  all  claims  in  full, 
and  succeeded  in  doing  so  only  after  nearly  five  years  of  unremitting 
industry,  close  economy,  and  absolute  personal  sacrifices.  As  a 
philanthropist  and  a  sincere  and  earnest  Christian,  zealous  in  every 
good  work,  his  memory  is  cherished  by  many  to  whom  his  contri- 
butions to  locomotive  improvement  are  comparatively  unknown. 
From  the  earliest  years  of  his  business  life  the  practice  of  systematic 
benevolence  was  made  a  duty  and  a  pleasure.     His  liberality  con- 


HISTORY   OF   THE    STEAM-ENGINE.  ^xix 

stantly  increased  with  his  means.  Indeed^  he  would  unhesitatingly 
give  his  notes,  in  large  sums,  for  charitable  purposes  when  money 
was  absolutely  wanted  to  carry  on  his  business.  Apart  from  the 
thousands  which  he  expended  in  private  charities,  and  of  which,  of 
course,  little  can  be  known,  Philadelphia  contains  many  monuments 
of  his  munificence. 

After  the  death  of  Mr.  Baldwin  the  business  was  reorganized,  in 
1867,  under  the  title  of  "  The  Baldwin  Locomotive  Works,"  M. 
Baird  &  Co.,  Proprietors.  Messrs.  George  Burnham  and  Charles  T, 
Parry,  who  had  been  connected  with  the  establishment  from  an  early 
period,  the  former  in  charge  of  the  finances,  and  the  latter  as  General 
Superintendent,  were  associated  with  Mr.  Baird  in  the  copartnership. 
Three  years  later,  Messrs.  Edward  H.  Williams,  William  P.  Henszey, 
and  Edward  Longstreth  became  members  of  the  firm.  Mr.  Williams 
had  been  connected  with  railway  management  on  various  lines  since 
-1850.  Mr.  Henszey  had  been  Mechanical  Engineer,  and  Mr.  Long- 
streth the  General  Superintendent  of  the  works  for  several  years 
previously. 

The  production  of  the  Baldwin  Locomotive  Works  from  1866  to 
1 87 1,  both  years  inclusive,  was  as  follows  : 

1866,  one  hundred  and  eighteen  locomotives. 

1867,  one  hundred  and  twenty-seven     " 

1868,  one  hundred  and  twenty-four       " 

1869,  two  hundred  and  thirty-five  " 

1870,  two  hundred  and  eighty  " 

1 87 1,  three  hundred  and  thirty-one        " 

In  July,  1866,  the  engine  Consolidation  was  built  for  the 
Lehigh  Valley  Railroad,  on  the  plan  and  specification  furnished  by 
Mr.  Alexander  Mitchell,  Master  Mechanic  of  the  Mahanoy  Division 
of  that  railroad.  This  engine  was  intended  for  working  the  Mahanoy 
plane,  which  rises  at  the  rate  of  one  hundred  and  thirty-three  feet 
per  mile.  The  Consolidation  had  cylinders  twenty  by  twenty- 
four,  four  pairs  of  wheels  connected,  forty-eight  inches  in  diameter, 
and  a  Bissell  pony-truck  in  front,  equalized  with  the  front  driving- 
wheels.  The  weight  of  the  engine,  in  working  order,  was  ninety 
thousand  pounds,  of  which  all  but  about  ten  thousand  pounds  was 
on  the  drivings-wheels.     This  engine  has  constituted  the  first  of  a 


(^XX  HISTORY   OF   THE   STEAM-ENGINE. 

class  to  which  it  has  given  its  name,  and  Consolidation  engines 
have  since  been  constructed  for  a  large  number  of  railways,  not  only 
in  the  United  States,  but  in  Mexico,  Brazil,  and  Australia. 

A  class  of  engines  known  as  Moguls,  with  three  pairs  of 
wheels  connected  and  a  swinging  pony-truck  in  front  equalized 
with  the  forward  driving-wheels,  took  its  rise  in  the  practice  of  this 
establishment  from  the  E.  A.  Douglas,  built  for  the  Thomas  Iron 
Company,  in  1867.  Several  sizes  of  Moguls  have  been  built, 
but  principally  with  cylinders  sixteen  to  nineteen  inches  in  di- 
ameter, and  twenty-two  or  twenty-four  inches  stroke,  and  with  driv- 
ing-wheels from  forty-four  to  fifty-seven  inches  in  diameter.  This 
plan  of  engine  has  rapidly  grown  in  favor  for  freight  service  on 
heavy  grades  or  where  maximum  loads  are  to  be  moved,  and 
has  been  adopted  by  several  leading  lines.  Utilizing,  as  it  does, 
nearly  the  entire  weight  of  the  engine  for  adhesion,  the  main  and 
back  pairs  of  driving-wheels  being  equalized  together,  as  also 
the  front  driving-wheels  and  the  pony-wheels,  and  the  construc- 
tion of  the  engine  with  swing-truck  and  one  pair  of  driving-wheels 
without  flanges  allowing  it  to  pass  short  curves  without  difficulty, 
the  Mogitl  is  generally  accepted  as  a  type  of  engine  especially 
adapted  to  the  economical  working  of  heavy  freight  traffic. 

In  1867,  on  a  number  of  eight-wheeled  four-coupled  engines  for 
the  Pennsylvania  Railroad,  the  four-wheeled  swing-bolster-truck  was 
first  applied,  and  thereafter  a  large  number  of  engines  have  been  so 
constructed.  The  two-wheeled  or  "  pony-truck "  has  been  built 
both  on  the  Bissell  plan,  with  double  inclined  slides,  and  with  the 
ordinary  swing-bolster,  and  in  both  cases  with  the  radius-bar  pivot- 
ing from  a  point  about  four  feet  back  from  the  centre  of  the  truck. 
The  four-wheeled  truck  has  been  made  with  swinging  or  sliding 
bolster,  and  both  with  and  without  the  radius-bar.  Of  the  engines 
above  referred  to  as  the  first  on  which  the  swing-bolster-truck  was 
applied,  four  were  for  express  passenger  service,  with  driving-wheels 
sixty-seven  inches  in  diameter,  and  cylinders  seventeen  by  twenty- 
four.  One  of  them,  placed  on  the  road  September  9,  1867,  was  in 
constant  service  until  May  14,  1871,  without  ever  being  off  its 
wheels  for  repairs,  making  a  total  mileage  of  one  hundred  and  fifty- 
three  thousand  two  hundred  and  eighty  miles.  All  of  these  engines 
have  their  driving-wheels  spread  eight  and  one-half  feet  between 
centres. 


HISTORY   OF   THE   STEAM-ENGINE.  ^Xxi 

Steel  flues  were  first  used  in  three  ten-wheeled  fi-eight  engines, 
Numbers  2ii,  338,  and  368,  completed  for  the  Pennsylvania  Rail- 
road in  August,  1868.  Flues  of  the  same  material  have  also  been 
used  in  a  number  of  engines  for  South  American  railroads.  Expe- 
rience with  tubes  of  this  metal,  however,  has  not  yet  been  sufficiently 
extended  to  show  whether  they  give  any  advantages  commensurate 
with  their  increased  cost  over  iron. 

Steel  boilers  were  first  made  in  1868  for  locomotives  for  the  Penn- 
sylvania Railroad  Company,  and  the  use  of  this  material  for  the 
barrels  of  boilers  as  well  as  for  the  fire-boxes  has  continued  to  some 
extent.  Steel  plates  somewhat  thinner  than  if  of  iron  have  been 
generally  used,  but  at  the  same  time  giving  an  equal  or  greater 
tensile  strength.  The  thoroughly  homogeneous  character  of  the 
steel  boiler-plate  made  in  this  country  recommends  it  strongly  for 
the  purpose. 

In  1854  four  engines  for  the  Pennsylvania  Railroad  Company, 
the  Tiger,  Leopard,  Hornet  and  Wasp,  were  built  with  straight 
boilers  and  two  domes  each,  and  in  1866  this  method  of  con- 
struction was  revived.  Since  that  date  the  practice  of  the  estab- 
lishment has  included  both  the  wagon-top  boiler  with  single  dome, 
and  the  straight  boiler  with  one  or  two  domes.  When  the  straight 
boiler  is  used  the  waist  is  made  about  two  inches  larger  in  diameter 
than  that  of  the  wagon-top  form.  About  equal  space  for  water  and 
steam  is  thus  given  in  either  case,  and,  as  the  number  of  flues  is  the 
same  in  both  forms,  more  room  for  the  circulation  of  water  between 
the  flues  is  afforded  in  the  straight  boiler,  on  account  of  its  larger 
diameter,  than  in  the  wagon-top  shape.  Where  the  straight  boiler 
is  used  with  two  domes  the  throttle- valve  is  placed  in  the  forward 
dome. 

In  1868,  a  locomotive  of  three  and  a  half  feet  gauge  was  con- 
structed for  the  Averill  Coal  and  Oil  Company,  of  West  Virginia. 
This  was  the  first  narrow-gauge  locomotive  in  the  practice  of  the 
works. 

In  1869  three  locomotives  of  the  same  gauge  were  constructed  for 
the  Uniao  Valenciana  Railway  of  Brazil,  and  were  the  first  narrow- 
gauge  locomotives  constructed  at  these  works  for  general  passenger 
and  freight  traffic.  In  the  following  year  the  Denver  and  Rio 
Grande  Railway,  of  Colorado,  was  projected  on  the  three-feet  gauge, 
and  the  first  locomotives  for  the  line  were  designed  and  built  in 


CXXll 


HISTORY   OF   THE   STEAM-ENGINE. 


1 87 1.  Two  classes,  for  passenger  and  freight  respectively,  were 
constructed.  The  former  were  six-wheeled,  four  wheels  coupled 
forty  inches  in  diameter,  nine  by  sixteen  cylinders,  and  weighed 
each,  loaded,  about  twenty-five  thousand  pounds.  The  latter  were 
eight-wheeled,  six  wheels  coupled  thirty-six  inches  in  diameter, 
eleven  by  sixteen  cylinders,  and  weighed  each,  loaded,  about  thirty- 
five  thousand  pounds.  Each  had  a  swinging-truck  of  a  single  pair 
of  wheels  in  front  of  the  cylinders.  The  latter  type  has  been  main- 
tained for  freight  service  on  most  narrow-gauge  lines,  but  principally 
of  larger  sizes,  engines  as  heavy  as  fifty  thousand  pounds  having 
been  turned  out.  The  former  type  for  passenger  service  was  found 
to  be  too  small  and  to  be  unsteady  on  the  track,  owing  to  its  com- 
paratively short  wheel-base.     It  was  therefore  abandoned,  and  the 


FREIGHT    LOCOMOTIVE,    "  CONSOLIDATION  "    TYPE. 

^)rdinary  "American  "  pattern,  eight-wheeled,  four-coupled,  substi- 
tuted. Following  the  engines  for  the  Denver  and  Rio  Grande 
Railway,  others  for  other  narrow-gauge  lines  were  called  for,  and 
the  manufacture  of  this  description  of  rolling  stock  soon  assumed 
importance.  From  1868  to  1870,  inclusive,  eleven  narrow-gauge 
locomotives  were  included  in  the  product.  The  number  of  narrow- 
gauge  locomotives  built  in  succeeding  years  has  been  as  follows : 
1871,  thirty-two;  1872,  nineteen;  1873,  twenty-nine;  1874,  forty- 
four;  1875,  thirty-six;  1876,  fifty  one ;  1877,  sixty-five;  1878,  sev- 
enty-five ;  1 879,  seventy-eight. 

The  Consolidation  type,  as  first  introduced  for  the  four  feet 
eight  and  one-half  inches  gauge  in  1866,  was  adapted  to  the  three- 
feet  gauge  in  1873.  In  1877  a  locomotive  on  this  plan,  weighing  in 
working  order  about  sixty  thousand  pounds,  with  cylinders  fifteen 


HISTORY   OF   THE   STEAM-ENGINE.  CXXUl 

by  twenty,  was  built  for  working  the  Garland  extension  of  the 
Denver  and  Rio  Grande  Railway,  which  crosses  the  Rocky  Moun- 
tains with  maximum  grades  of  two  hundred  and  eleven  feet  per  mile, 
and  minimum  curves  of  thirty  degrees.  The  performance  of  this 
locomotive,  the  Alamosa,  is  given  in  the  following  extract  from  a 
letter  from  the  then  General  Superintendent  of  that  railway  : 

"Denver,  Col.,  Aug.  31,  1877. 

"  On  the  29th  inst.  I  telegraphed  you  from  Veta  Pass — Sangre  de  Cristo  Mountains — 
that  engine  Alamosa  had  just  hauled  from  Garland  to  the  Summit  one  baggage  car 
and  seven  coaches,  containing  one  hundred  and  sixty  passengers.  Yesterday  I  received 
your  reply  asking  for  particulars,  etc. 

"  My  estimate  of  the  weight  was  eighty-five  net  tons,  stretched  over  a  distance  of  three 
hundred  and  sixty  feet,  or  including  the  engine,  of  four  hundred  and  five  feet. 

"  The  occasion  of  this  sized  train  was  an  excursion  from  Denver  to  Garland  and 
return.  The  night  before,  in  going  over  from  La  Veta,  we  had  over  two  hundred  pas. 
sengers,  but  it  was  8  P.  M.,  and,  fearing  a  slippery  rail,  I  put  on  engine  No.  19  as  m 
pusher,  although  the  engineer  of  the  Alamosa  said  he  could  haul  the  train,  and  I 
believe  he  could  have  done  so.  The  engine  and  train  took  up  a  few  feet  more  than  the 
half  circle  at  '  Mule  Shove,'  where  the  radius  is  one  hundred  and  ninety-three  feet.  The 
engine  worked  splendidly,  and  moved  up  the  two  hundred  and  eleven  feet  grades  and 
around  the  thirty  degree  curves  seemingly  with  as  much  ease  as  our  passenger  engines 
on  seventy-five  feet  grades  with  three  coaches  and  baggage  cars. 

"  The  Alamosa  hauls  regularly  eight  loaded  cars  and  caboose,  about  one  hundred 
net  tons ;  length  of  train  about  two  hundred  and  thirty  feet. 

"  The  distance  from  Garland  to  Veta  Pass  is  fourteen  and  one- quarter  miles,  and  the 
time  is  one  hour  and  twenty  minutes.  Respectfully  yours, 

(Signed)  "  W.  W.  Borst,  Stiff." 

In  addition  to  narrow-gauge  locomotives  for  the  United  States, 
this  branch  of  the  product  has  included  a  large  number  of  one-metre 
gauge  locomotives  for  Brazil,  three-feet  gauge  locomotives  for  Cuba, 
Mexico,  and  Peru,  and  three  and  one-half  feet  gauge  stock  for  Costa 
Rica,  Nicaragua,  Canada,  and  Australia. 

Locomotives  for  single-rail  railroads  were  built  in  1878  and  early 
in  1879,  adapted  respectively  to  the  systems  of  General  Roy  Stone 
and  Mr.  W.  W.  Riley. 

In  1870,  in  some  locomotives  for  the  Kansas  Pacific  Railway,  the 
steel  tires  were  shrunk  on  without  being  secured  by  bolts  or  rivets 
in  any  form,  and  since  that  time  this  method  of  putting  on  tires  has 
been  the  rule. 

In  1871  forty  locomotives  were  constructed  for  the  Ohio  and  Mis- 
sissippi Railway,  the  gauge  of  which  was  changed  from  five  feet  six 


CXXIV 


HISTORY   OF   THE   STEAM-ENGINE. 


inches  to  four  feet  eight  and  one-half  inches.  The  entire  lot  of  forty 
locomotives  was  completed  and  delivered  in  about  twelve  weeks. 
The  gauge  of  the  road  was  changed  on  July  4th,  and  the  forty 
locomotives  went  at  once  into  service  in  operating  the  line  on  the 
standard  gauge. 

The  product  of  the  works,  which  had  been  steadily  increasing  for 
some  years  in  sympathy  with  the  requirements  of  the  numerous 
new  railroads  which  were  constructing,  reached  three  hundred  and 
thirty-one  locomotives  in  1871,  and  four  hundred  and  twenty-two  in 
1872.  Orders  for  ninety  locomotives  for  the  Northern  Pacific  Rail- 
road were  entered  during  1870-71,  and  for  one'hundred  and  twenty- 
four  for  the  Pennsylvania  Railroad  during  1872-73,  and  mostly 
executed  during  those  years.  A  contract  was  also  made  during 
1872  with  the  Veronej-Rostofif  Railway  of  Russia  for  ten  locomo- 
tives to  burn  Russian  anthracite  coal.  Six  were  Moguls,  with 
cylinders  nineteen  by  twenty-four,  and  driving-wheels  four  and  one- 
half  feet  diameter;  and  four  were  passenger  locomotives,  "American" 
pattern,  with  cylinders  seventeen  by  twenty-four,  and  driving-wheels 
five  and  one-half  feet  diameter.  Nine  "American"  pattern  locomo- 
tives, fifteen  by  twenty-four  cylinders,  and  five-feet  driving-wheels, 
were  also  constructed  in  1872-73  for  the  Hango-Hyvinge  Railway 
of  Finland. 

Early  in  1873  Mr.  Baird  sold  his  interest  in  the  works  to  his  five 
partners,  and  a  new  firm  was  formed  under  the  style  of  Burnham, 
Parry,  Williams  &  Co.,  dating  from  January  1st  of  that  year.  Mr. 
John  H.  Converse,  who  had  been  connected  with  the  works  since 
1870,  became  a  member  of  the  new  firm.  The  product  of  this  year 
was  four  hundred  and  thirty-seven  locomotives,  the  greatest  in  the 
history  of  the 'business.  During  a  part  of  the  year  ten  locomotives 
per  week  .were  turned  out.  Nearly  three  thousand  men  were 
employed.  Forty-five  locomotives  for  the  Grand  Trunk  Railway 
of  Canada  were  built  in  August,  September,  and  October,  1873,  and 
all  were  delivered  in  five  weeks  after  shipment  of  the  first.  As  in 
the  case  of  the  Ohio  and  Mississippi  Railway,  previously  noted, 
these  were  to  meet  the  requirements  of  a  change  of  gauge  from  five 
and  one-half  feet  to  four  feet  eight  and  one-half  inches.  Two 
Consolidation  locomotives  were  sent  in  September,  1873,  to  the 
Mexican  Railway.  These  had  cylinders  twenty  by  twenty-four; 
drivtrig-wheels  forty-nine  iaehes  jn, diameter;  and  weighed,  loaded. 


HISTORY   OF   THE   STEAM-ENGINE.  CXXV 

about  95,000  pounds  each,  of  which  about  82,000  pounds  were  on 
the  driving-wheels.  These  engines  hauled  in  their  trial  trips,  with- 
out working  to  their  full  capacity,  five  loaded  cars  up  the  four  per 
cent,  grades  of  the  Mexican  Railway.  In  November,  1873,  under 
circumstances  of  especial  urgency,  a  small  locomotive  for  the  Meier 
Iron  Company  of  St.  Louis  was  wholly  made  from  the  raw  material 
in  sixteen  working  days. 

The  financial  difficulties  which  prevailed  throughout  the  United 
States,  beginning  in  September,  1873,  and  affecting  chiefly  the  rail- 
road interests  and  all  branches  of  manufacture  connected  therewith, 
have  operated  of  course  to  curtail  the  production  of  locomotives 
since  that  period.  Hence,  only  two  hundred  and  five  locomotives 
were  built  in  1874,  and  one  hundred  and  thirty  in  1875.  Among 
these  may  be  enumerated  two  sample  locomotives  for  burning 
anthracite  coal  (one  passenger,  sixteen  by  twenty-four  cylinders,  and 
one  Mogul  freight,  elgiiteen  by  twenty-four  cylinders)  for  the 
Technical  Department  of  the  Russian  Government;  also,  twelve 
Mogul  freight  locomotives,  nineteen  by  twenty-four  cylinders,  for 
the  Charkoff  Nicolaieff  Railroad  of  Russia,  A  small  locomotive  to 
work  by  compressed  air,  for  drawing  street  cars,  was  constructed 
during  1874  for  the  Compressed  Air  Locomotive  and  Street  Car 
Company  of  Louisville,  Ky.  It  had  cylinders  seven  by  twelve,  and 
four  wheels  coupled,  thirty  inches  in  diameter.  Another  and  smaller 
locomotive  to  work  by  compressed  air  was  constructed  three  years 
later  for  the  Plymouth  Cordage  Company  of  Massachusetts,  for 
service  on  a  track  in  and  about  their  works.  It  had  cylinders  five 
by  ten,  four  wheels  coupled  twenty-four  inches  diameter,  weight, 
seven  thousand  pounds,  and  has  been  successfully  employed  for 
the  work  required. 

The  year  1876,  noted  as  the  year  of  the  Centennial  International 
Exhibition  in  Philadelphia,  brought  some  increase  of  business,  and 
two  hundred  and  thirty-two  locomotives  were  constructed.  An 
exhibit  consisting  of  eight  locomotives  was  prepared  for  this  occa- 
sion. With  the  view  of  illustrating  not  only  different  types  of 
American  locomotives,  but  the  practice  of  different  railroads,  the 
exhibit  consisted  chiefly  of  locomotives  constructed  to  fill  orders 
from  various  railroad  companies  of  the  United  States  and  from  the 
Imperial  Government  of  Brazil.  A  Consolidation  locomotive  for 
burning  anthracite  coal,  for  the  Lehigh  Valley  Railroad,  for  which 


CXXvi  HISTORY   OF   THE   STEAM-ENGINE. 

line  the  first  locomotive  of  this  type  was  designed  and  built  in  1866; 
a  similar  locomotive,  to  burn  bituminous  coal,  and  a  passenger 
locomotive  for  the  same  fuel  for  the  Pennsylvania  Railroad;  a 
Mogul  freight  locomotive,  the  Principe  do  Grao  Para,  for  the  D. 
Pedro  Segundo  Railway  of  Brazil;  and  a  passenger  locomotive 
(anthracite  burner)  for  the  Central  Railroad  of  New  Jersey,  com- 
prised the  larger  locomotives  contributed  by  these  works  to  the 
Exhibition  of  1876.  To  these  were  added  amine  locomotive  and 
two  narrow  (three  feet)  gauge  locomotives,  which  were  among  those 
used  in  working  the  Centennial  Narrow-Gauge  Railway. 

Steel  fire-boxes  with  vertical  corrugations  in  the  side  sheets  were 
first  made  by  these  Works  early  in  1876,  in  locomotives  for  the 
Central  Railroad  of  New  Jersey,  arid  for  the  Delaware,  Lackawanna 
and  Western  Railway. 

The  first  American  locomotives  of  New  South  Wales  and  Queensi- 
land  were  constructed  by  the  Baldwin  Locomotive  Works  in  1877, 
and  were  succeeded  by  additional  orders  in  1878  and  1879.  Si\(i 
locomotives  of  the  Consolidation  type  for  three  and  one-half  feet 
gauge  were  also  constructed  in  the  latter  year  for  the  Government 
Railways  of  New  Zealand,  and  two  freight  locomotives,  six-wheels;- 
connected  with  forward  truck,  for  the  Government  of  Victoria. 
Four  similar  locomotives  (ten-wheeled,  six-coupled,  with  sixteen 
by  twenty-four  cylinders)  were  also  built  during  the  same  year  for 
the  Norwegian  State  Railways. 

Forty  heavy  Mogid  locomotives  (nineteen  by  twenty-four  cylin- 
ders, driving-wheels  four  and  one-half  feet  in  diameter)  were  con- 
structed early  in  1878  for  two  Russian  Railways  (the  Koursk 
Charkof  Azof,  and  the  Orel  Griazi).  The  definite  order  for  these 
locomotives  was  only  received  on  the  sixteenth  of  December,  1877, 
and  as  all  were  required  to  be  delivered  in  Russia  by  the  following 
May,  especial  despatch  was  necessary.  The  working  force  was  in- 
creased from  eleven  hundred  to  twenty-three  hundred  men  in  about 
two  weeks.  The  first  of  the  forty  engines  was  erected  and  tried 
under  steam  on  January  5th,  three  weeks  after  receipt  of  order,  and 
was  finished,  ready  to  dismantle  and  pack  for  shipment,  one  week 
later.  The  last  engine  of  this  order  was  completed  February  13th. 
The  forty  engines  were  thus  constructed  in  about  eight  weeks,  be- 
sides twenty-eight  additional  engines  on  other  orders,  which  were 
constructed  wholly  or  partially  and  shipped  during  the  same  period. 


HISTORY   OF   THE   STEAM-ENGINE. 


CXXVll 


In  December,  1878,  the  heaviest  locomotive  ever  built  at  these 
Works  was  completed  for  the  New  Mexico  and  Southern  Pacific 
Railroad  (four  feet  eight  and  one-half  inches  gauge),  an  extension 
of  the  Atchison,  Topeka  and  Santa  Fe  Railway.  It  was  of  the 
Consolidation  type,  was  named  Uncle  Dick,  and  was  of  the  following 
general  dimensions  :  Cylinders,  twenty  by  twenty-six  inches ;  driv- 
ing-wheels, forty-two  inches  diameter,  four  pairs  connected ;  truck- 
wheels,  thirty  inches  diameter,  one  pair  ;  total  wheel-base,  twenty- 
two  feet  ten  inches ;  wheel-base  of  flanged  driving-wheels,  nine 
feet;  capacity  of  water-tank  on  boiler,  twelve  hundred  gallons; 
capacity  of  water-tank  of  separate  tender,  twenty-five  hundred 
gallons;  weight  of  engine  in  working-order,  including  water  in 
tank,  one  hundred  and  fifteen  thousand  pounds  ;  weight  on  driving- 
wheels,  one  hundred  thousand  pounds. 

This  locomotive  was  built  for  working  a  temporary  switchback 
track  (used  during  the  construction  of  a  tunnel)  crossing  the  Rocky 
Mountains,  with  maximum  grades  of  six  in  one  hundred.  Over 
these  grades  the  engine  hauled  its  loaded  tender  (forty-four  thou- 
sand pounds)  and  nine  loaded  cars  (each  forty-three  thousand 
pounds) :  total  load,  exclusive  of  its  own  weight,  four  hundred  and 
thirty-one  thousand  pounds.  On  a  grade  of  two  per  cent,  it  hauled 
a  train  weighing  nine  hundred  and  sixty-five  thousand  pounds,  and 
on  one  of  three  and  a  half  per  cent,  five  hundred  and  seventeen 
thousand  pounds.  Curves  of  sixteen  degrees  occurred  on  the 
switchback  track,  but  not  in  combination  with  the  six  per  cent 
grades. 

The  production  during  the  eighteen  years  from  1872  to  1890  inclu- 
sive was  as  follows : 


1872 

1873 
1874 
1875 
1876 
1877 
1878 
1879 
1880 
1881 
1882 


422 

locomotives 

437 

« 

205 

u 

130 

« 

232 

M 

185 

(( 

292 

M 

398 

M 

517 

M 

555 

M 

563 

u 

CXXVIU 


HISTORY   OF  THE   STEAM-ENGINE. 


1883 
1884 
1885 
1886 
1887 
1888 
1889 
1890 
189I 


557    locomotives. 


429 

242 

u 

550 

u 

653 

u 

737 

« 

827 

u 

946 

i( 

1050* 

"  (estimated) 

FREIGHT    LOCOMOTIVE,    "  MOGUL        TYPE. 

The  year  1891  is  marked  by  the  largest  production  in  the  his- 
tory of  the  Works,  and  the  character  of  the  product  reflects  the 
growing  demand  for  larger  and  more  powerful  locomotives. 

*  Compare  this  with  the  following :   In   1838  the  United  States  Government  made  a 

request  for  statistics  of  steamboats,  locomotiveo  and  stationary  engines,  with  the  following 

result : 

800         .         .         .  Steamboats, 

350         .  .  .  Locomotives,  and 

1861  .  .  .  Stationary  Engines. 

Of  the  latter  383  were  in  Pennsylvania,  and  Louisiana  came  second  on  the  list,  274. 
which  were  used  chiefly  on  the  sugar  plantations.  Massachusetts  came  next  with  165  ; 
New  York,  87  ;  Ohio,  83  ;  the  rest  distributed  among  the  States.  The  800  steamboats 
were  either  all  coasters  or  river  boats,  and  akhough  the  Savannah,  built  in  New  York  in 
X819,  had  been  the  first  to  cross  the  Atlantic,  there  was  not  one  classed  as  an  ocean 
steamer.  The  largest  was  a  government  vessel,  The  Natchez,  860  tons  measurement, 
300  horse-power.  There  were  350  locomotives  reported,  90  of  which  were  in  Pennsyl- 
vania; Massachusetts,  37 ;  Virginia,  34;  New  Jersey,  32 ;  Maryland,  31;  New  York, 
28 ;  South  Carolina,  27.     No  other  State  had  more  than  10  owned  within  its  limits. 


HISTORY  OF   THE   STEAM-ENGINE. 


CXXtX 


In  order  to  show  the 
importance  of  the  industry 
devoted  to  the  manufact- 
ure of  locomotives,  we 
give  a  list  of  twelve  first- 
class  establishments 
throughout  the  United 
States  engaged  in  the 
manufacture,  besides  the 
Baldwin  Locomotive 
Works  described.  Our 
space  forbids  our  entering 
into  anything  like  a  de- 
tail of  what  is  accom- 
plished by  these  estab- 
lishments :  Brooks  Loco- 
motive Works,  Dunkirk, 
N.  Y.;  Cooke  Locomotive 
&  Machine  Co.,  Paterson, 
N.  J. ;  Hinkley  Locomo- 
tive Co.,  Boston,  Mass. ; 
Manchester  Locomotive 
Co.,  Manchester,  N.  H. ; 
New  York  Locomotive 
Works,  Rome,  N.  Y. ; 
Pittsburgh  Locomotive  & 
Car  Works,  Pittsburgh ; 
H.  K.  Porter  &  Co., 
Pittsburgh,  Pa. ;  Rhode 
Island  Locomotive 
Works,  Providence;  Rich- 
mond Locomotive  & 
Machine  Works,  Rich- 
mond, Va. ;  Rogers  Loco- 
motive &  Machine  Works, 
Paterson,  N.  J. ;  Sche- 
nectady Locomotive  Works,  Schenectady,  N.  Y. ;  Taunton  Locomo- 
tive Manufacturing  Co.,  Taunton,  Mass. 
Tfe  Wootten  Fire-box. — One  of  the  latest  novelties  in  locomotive 


cxxx 


HISTORY   OF   THE   STEAM-ENGINE. 


building  has  been  achieved  in  rather  an  indirect  manner  by  Mr.  John 
E.  Wootten,  formerly  Manager  of  the  Philadelphia  and  Reading  Rail- 
road Company.  It  had  occurred  to  Mr.  Wootten  that  the  enor- 
mous amount  of  slack  or  refuse  coal,  which  is  to  be  found  around 
all  coal  mines,  might  possibly  be  utilized  in  locomotive  fire-boxes, 
where  the  opportunity  of  an  enormous  draught  is  possible.  He 
therefore  patented  a  fire-box  with  a  very  large  surface,  indeed,  so 
large  that,  whereas  the  fire-box  in  general  use  presents  a  surface  of 
about  twenty-six  square  feet  between  the  wheels,  Mr.  Wootten,  by 
lifting  his  fire-box  above  the  wheels,  was  able  to  utilize  a  fire-box 
with  about  seventy-five  square  feet  surface.  There  is  a  fire-brick 
arch  or  division,  which  is  a  very  essential  point  in  the  design  of  the 
Wootten  fire-box,  and  gives  much  of  the  success  of  the  engines  in 
getting  the  necessary  draught  for  burning  fine  coal  or  slack.  Be- 
sides the  advantage  that  it  gives  of  utilizing  what  was  formerly 
worthless  waste  coal,  these  engines  make  steam  freely,  and  haul  the 
heavy  express  trains  of  the  Union  Pacific  at  a  higher  rate  of  speed 
than  has  ever  before  been  attained  on  that  road.  The  coal  used  is 
taken  from  the  mines  owned  by  the  railroad,  and  is  bituminous, 
though  light,  in  its  character.  It  is,  however,  successfully  burned 
without  any  sparks,  a  result,  of  course,  due  to  the  enormous  grate 
area,  while  the  heat  radiated  from  the  arch  fire-bricks  or  wall 
maintains  an  even  temperature  and  insures  complete  combustion. 
The  large  area  of  the  grate  prevents  any  appreciable  lifting  of  the 
fire,  and  the  small  pieces  of  live  coal  that  are  sucked  up  by  the 
blast  are  burned  on  their  way  to  the  flues,  owing  to  the  high  tem- 
perature of  the  brick  arch.  In  the  Wootten  express  engine,  of 
which  we  give  an  illustration,  it  will  be  seen  from  the  prospective 
view  of  the  engine  and  tender,  that  the  engines  have  two  cabs,  and 
thus  the  fireman  is  more  efficiently  sheltered  from  the  weather  than 
is  usual  on  other  engines.  The  severe  climate  of  Nebraska  and 
Wyoming  in  winter  necessitates  a  very  efficient  protection  for  the 
men  working  the  engines,  and  the  arrangement  shown,  we  are  told, 
is  found  to  answer  well. 

The  engine  referred  to  above  is  one  of  a  large  class  built  by  the 
Rogers  Locomotive  Works,  of  Paterson,  New  Jersey,  for  the  Union 
Pacific  Railway,  from  the  designs  of  Mr.  Clement  Hackney,  Super^ 
intendent  of  Motive  Power  of  that  line.  Further  illustrations  of 
American  locomotives  will  be  found  on  the  large  plates  at  page  68o- 


HISTORY  OF  THE  STEAM-ENGINE 


CXXXl 


MODERN   HIGH   DUTY   PUMPING   ENGINES. 

See  Stationary  Engines,  pages  150—346. 

The  HoUy-Gaskill  High  Duty  Pumping  Engine  was  designed 
by  Mr.  Harvey  F.  Gaskill  in  1881,  and  first  introduced  at  the 
Saratoga  Springs,  New  York,  water  works,  by  the  Holly  Manu- 
facturing Company,  of  Lockport,  New  York,  in  1882,  and  has  since 
been  duplicated  in  various  sizes  in  many  prominent  public  works  in 
the  United  States  :  notably  at  Philadelphia,  Boston,  Chicago,  Wash- 
ington and  Buffalo. 

The  engine  is  horizontal,  of  the  rotative  beam  non-receiver  com- 
pound type,  and  involves  several  novel  features  of  construction, 


Fig.  a. — Side  Elevation. — HoUy-Gaskill  Pumping  Engine,  Saratoga  Springs  Water  Works. 

whereby  a  large  capacity  and  a  high  economy  are  obtained  by  a 
simple  machine  in  a  small  compass. 

In  its  construction  a  heavy  cast-iron  bed  plate  is  provided,  upon 
which  are  mounted  two  double-acting  reciprocating  plunger  pumps, 
and  in  direct  line  therewith  two  low-pressure  steam  cylinders  (see 
accompanying  cuts),  with  the  piston  rods  of  the  latter  connected 
directly  to  the  piston  rods  of  the  former. 

Between  these  pumps  and  steam  cylinders  there  are  placed  two 
beam  supports,  which  are  firmly  bolted  to  the  bed  plate  and  rigidly 


cxxxu 


HISTORY  OF  THE  STEAM-ENGINE. 


stayed  by  wrought-iron  struts  to  the  pumps  and  steam  cylinders. 
These  beam  supports  carry  the  beam  shafts  and  beams,  the  lower 
end  of  the  latter  being  connected  to  the  cross-head  of  the  low- 
pressure  cylinders  by  suitable  links. 

On  top  of  the  pumps  are  placed  heavy  bearings  supporting  the 


Fig.  b. — External  and  Sectional  End  Views  of  Steam  Cylinders.— HoUy-Gaskill 
Pumping  Engine,  Saratoga  Springs  Water  Works. 

main  shaft  and  fly-wheel,  which  are  common  to  both  pumps  and  the 
cranks,  the  latter  being  keyed  to  the  shaft  at  quarters  or  right-angles 
to  each  other. 

On  the  tops  of  the  low-pressure  steam  cylinders  are  mounted  two 
high-pressure  steam  cylinders  with  their  centres  in  the  same  hori- 
zontal plane  as  the  centre  of  the  main  crank   shaft.     Two  cross- 


HISTORY   OF  THE  STEAM-ENGINE.  CXXxiii 

heads  for  the  high-pressure  steam  cyHnders  are  connected  by  hnks 
to  the  upper  ends  of  the  beams,  and  the  beams  are  in  turn  connected 
to  the  crank  pins  by  connecting  rods  of  the  usual  form,  so  that 
each  pair  of  steam  pistons  drive  one  pump.  The  steam  cylinders  are 
all  steam  jacketed,  sides  and  heads,  the  condensation  from  which  is 
trapped  back  to  the  boilers. 

On  the  inner  end  of  each  beam  shaft  an  arm  is  keyed,  from 
which  the  air  pumps  are  driven. 

All  the  valves  of  the  steam  cylinders  are  operated  by  eccentrics 
keyed  to  two  counter-shafts,  which  are  placed  at  right-angles  with 
the  main  shaft,  and  are  driven  therefrom  by  two  pairs  of  mitre  gears. 

The  steam  valves  of  the  high-pressure  cylinders  are  of  the 
double  beat  poppet  pattern,  and  are  arranged  so  that  they  will 
always  open  at  the  beginning  of  the  stroke,  but  may  be  adjusted  to 
cut  off  the  steam  at  any  desired  point  of  the  stroke  at  the  will  of 
the  engineer. 

The  exhaust  valves  of  the  high-pressure  cylinders  are  of  the 
ordinary  slide  valve  type,  placed  intermediate  to  the  high  and  low- 
pressure  cylinders,  and  render  double  service  as  exhaust  valves  to 
the  former  and  admission  valves  to  the  latter.  They  are  set  so  that 
they  will  remain  open  until  the  stroke  is  nearly  completed,  allow- 
ing the  steam  to  pass  directly  and  freely  from  the  upper  to  the  lower 
cylinders.  The  exhaust  valves  of  the  low-pressure  cylinders  are 
of  the  same  type,  and  operate  in  the  same  manner. 

The  pumps  are  of  the  double-acting  plunger  type,  and  work 
reciprocally  through  internal  packed  glands  in  the  centres  of  the 
pump  chambers.  The  pump  valves  are  fixed  in  horizontal  plates 
below  and  above  the  line  of  plunger  travel,  those  at  one  end  of  the 
pump  being  divided  from  those  of  the  other  end  by  the  plunger 
glands.  Man-hole  plates  are  provided  for  access  to  the  plungers, 
glands  and  pump  valves.  These  pump  valves  are  of  a  peculiar  form, 
as  shown  by  the  accompaning  full-sized  cut.  Their  diameter  being 
small,  the  lift  is  slight,  and  yet  sufficient  to  give  an  area  of  water- 
way which  is  uniform  throughout.  The  same  size  is  used  in  all 
pumps,  the  number  being  proportioned  to  the  quantity  of  water 
required.  They  open  and  close  quickly  and  silently,  and  the  loss  of 
water  by  slippage  is  slight,  in  some  instances  less  than  one  per  cent. 
The  operation  of  the  machine  is  as  follows : 
Steam  is  admitted  through  the  double  beat  poppet  cut-off  valves 


CXXXIV 


HISTORY   OF   THE    STEAM-ENGINE. 


into  the  high-pressure  steam  cylinders,  and  forces  the  piston  forward 
under  full  boiler  pressure  until  the  point  of  cut-off  is  reached. 
These  valves  then  close  quickly,  and  the  remaining  portion  of  the 
stroke  is  accomplished  by  the  elastic  force  of  the  steam.  When 
these  pistons  have  nearly  reached  the  end  of  their  stroke,  the  ex- 


Fig.  c. — Sectional  and  External  End  Views  of  Pumps. — HoUy-Gaskill  Pumping  Engine, 
Saratoga  Springs  Water  Works. 

haust  valves  between  the  high  and  low-pressure  cylinders  open,  and 
the  steam  in  the  high-»pressure  cylinders  passes  immediately  into 
the  low-pressure  cylinders  and  against  their  pistons,  which  are  then 
at  the  end  of  their  stroke  and  opposite  the  high-pressure  pistons. 
The  low-pressure  pistons  are  then  in  turn  pushed  forward  by  the 
incoming  steam,  which  at  the  end  of  the  latter's  stroke  is  expanded 


HISTORY   OF  THE   STEAM-ENGINE.  CXXXV 

to  four  times  the  volume  it  had  in  the  high-pressure  cylinders  at  the 
time  of  its  release  therefrom.  The  release  from  the  low-pressure 
cylinders  is  accomplished  in  the  return  stroke  through  the  exhaust 
valves  into  the  condenser.  This  operation  is  repeated  in  each  pair 
of  cylinders  and  at  each  end  alternately.  The  close  connection 
between  each  pair  of  high  and  low-pressure  cylinders  reduces  the 
clearance  spaces  to  a  minimum,  which  with  thorough  jacketing 
insures  the  most  economical  use  of  steam. 

This  engine  is  built  to  operate  as  a  non-compound  engine,  in 
which  case  the  upper  or  high-pressure  cylinders  and  connections 
are  omitted,  the  poppet  cut-off  valves  being  placed  on  the  lower 
cylinders  and  steam  admitted  to  them  direct  from  the  boiler,  and 
then  exhausted  into  the  condenser.  This  mode  of  construction 
reduces  the  cost,  and  may  be  preferred  wherever  fuel  is  so  cheap 
that  economy  in  the  use  of  steam  becomes  a  less  important  matter 
than  the  purchase  price  of  the  machine  itself  When  constructeii 
in  this  way  the  duty  of  the  engine  is  reduced  about  thirty  per  cen:. 
as  compared  with  the  compound  engines. 

The  more  valuable  features  and  peculiar  merits  of  the  Holly- 
Gaskill  pumping  engine  are  as  follows  : 

First High  fuel  economy. 

Second Moderate  first  cost. 

Third Low  piston  speed. 

Fourth Simplicity  of  design. 

Fifth Accessibility  of  parts. 

Sixth    ....    Perfect  steam  distribution. 

Seventh Perfect  pump  action. 

Eighth       .     .     .    Uniform  length  of  stroke. 
Ninth    .     .     .      The  rough  steam  jacketing. 

This  engine  at  Saratoga  Springs  was  subjected  to  the  most  critical 
and  severe  tests  by  Professor  David  M.  Greene,  Director  Rens- 
selaer Polytechnic  Institute,  Troy,  N.  Y.,  on  the  part  of  the  builders; 
and  John  W.  Hill,  M.  E.,  of  Cincinnati,  Ohio,  in  behalf  of  the  Sara- 
toga Water  Board,  in  November,  1882;  the  result  of  which,  as 
officially  reported,  was  a  duty  of  112,899,993  pounds  of  water 
raised  one  foot,  with  one  hundred  pounds  of  coal  consumed  under 
the  boilers,  without  frictional  resistance  or  loss  of  effect,  and  without 
any  deductions  for  ashes,  clinkers,  or  unburned   coal  which   had 


CXXXVl 


HISTORY  OF  THE  STEAM-ENGINE. 


fallen  through  the  grates.  The  trial  was  a  continuous  run  of 
twenty  hours ;  the  coal  burned  was  Lackawanna  of  excellent 
quality;  the  average  water  pressure,  96.17  pounds;  average  steam 


Fig.  d. — Pump  Valve,  Full  Size. — HoUy-Gaskill  Pumping  Engine,  Saratoga  Springs  Water  Works. 


pressure,  74.25  pounds ;  average  vacuum,  27.28  inches ;  average 
temperature  of  feed  water  to  boilers,  169.17  F. ;  speed  of  pistons, 
107.25  per  minute ;  area  of  pump  plungers,  307.88  square  inches ; 
total  revolutions  during  the  trial,  21,449;  length  of  stroke,  thirty- 
six  inches;  and  total  coal  burned,  6,750  pounds. 


HISTORY   OF   THE   STEAM-ENGINE. 


CXXXVll 


These  remarkable  results  were  questioned  by  some  of  the  town 
officials ;  and,  at  their  request,  a  subsequent  trial  was  made  under 
the  sole  direction  and  care  of  Professor  Charles  T.  Porter,  inventor 
of  the  Porter-Allen  Steam  Engine,  in  June,  1883,  for  a  continuous 
run  of  sixty  hours;  resulting  in  an  actual  duty  of  106,838,000  foot- 
pounds for  the  entire  time,  with  an  apparent  duty  for  the  first  twelve 
hours  of  127,170,000  foot-pounds  per  100  pounds  of  coal  actually 
consumed.  It  should  be  stated  that  the  coal  used  during  the  last 
part  of  this  trial  was  of  inferior  quality. 

The  official  reports  of  the  Saratoga  Water  Commissioners  give 
this  engine  credit  for  an  average  duty  in  regular  daily  service  for 
the  years  1884  to  1890 — six  years — of  105,910,739  foot-pounds  per 
100  pounds  of  coal,  no  deductions  whatever  being  made  for  ashes, 
steam  for  heating,  or  other  purposes. 

Duty  trials  of  other  Holly-Gaskill  engines  of  this  type  show  the 
following  equally  remarkable  results  : 


Philadelphia,  Pa., 

1888, 

125,022,730  foot 

-pounds 

Buffalo,  N.  Y., 

1885, 

125,907,297 

« 

Buffalo.,  N.  Y., 

1889, 

122,255,512 

<( 

Dayton,  Ohio, 

1889, 

124,782,157 

« 

Erie,  Pa., 

1887, 

122,309,829 

« 

Chicago,  Ills., 

1886, 

110,632,166 

« 

Chicago,  Ills,, 

1887, 

102,583,585 

« 

Chicago,  Ills., 

1889 

108,600,000 

« 

Washington,  D.  C, 

1888 

101,772,977 

« 

Columbus,  Ohio, 

1884 

115,400,000 

(( 

Boston,  Mass., 

1888, 

109,421,000 

t( 

Also  at  Jackson,  Michigan;  Leavenworth,  Kansas;  Kalamazoo, 
Michigan ;  Lima,  Ohio ;  Port  Huron,  Michigan ;  Springfield,  Ohio ; 
each  of  which  shows  a  duty  exceeding  102,000,000  foot-pounds. 


CXXXviii  HISTORY   OF  THE   STEAM-ENGINE. 


THE  WORTHINGTON   PUMPING   ENGINE. 

Worthington  Compound  Condensing  Engines  of  large  capacity 
and  power,  and  of  the  form  and  type  herein  described,  have  been 
erected  in  nearly  five  hundred  pumping  stations,  with  an  aggregate 
daily  pumping  capacity  of  over  two  billion  gallons.  Beside  these, 
non-expanding  and  compound  engines,  ranging  in  capacity  from 
the  delivery  of  a  few  gallons  a  minute  to  several  millions  a  day 
have  been  constructed  to  the  number  of  over  fifty  thousand. 

In  referring  to  its  surprising  growth,  the  well-known  engineer, 
Mr.  E.  D.  Leavitt,  remarks,  in  a  paper  read  before  the  Montreal 
meeting  of  the  British  Association  of  Scientists  in  1884: 

"  This  (the  direct-acting)  class  of  pumping  machinery  deserves  a 
prominent  place,  as  the  number  in  use  vastly  exceeds  those  of  all 
other  types  combined.  The  first  consideration  will  be  given  to  the 
Worthington,  which  is  the  pioneer  of  its  type,  having  been  invented 
by  the  late  Henry  R.  Worthington,  and  patented  in  1844.  Mr. 
Worthington's  first  pump  was  designed  for  feeding  boilers.  His 
first  water-works  engine  was  built  for  the  city  of  Savannah,  Ga.,  and 
erected  in  1854.  ...  In  1863  Mr.  Worthington  brought  out  at 
Charlestown,  Mass.,  his  crowning  success,  the  Duplex  Engine,  which 
fairly 'deserves  to  be  placed  first  among  the  hydraulic  inventions  of 
this  century.  This  engine  has  since  been  more  extensively  dupli- 
cated for  water-works  purposes  than  any  other.  .  .  . 

"  Mr.  Worthington  and  his  successors  have  supplied  214  separate 
water  works  with  242  engines,  having  an  aggregate  daily  capacity  of 
910,000,000  gallons.*  This  is  equivalent  to  upwards  of  40  percent, 
of  the  estimated  capacity  of  all  the  water-works  pumping  engines 
in  America.  The  Duplex  Engines  have  been  made  of  capacities 
varying  from  500,000  to  25,000,000  gallons  per  day.  Their  action 
is  so  smooth  and  perfect  as  to  excite  the  admiration  of  all  behold- 
ers. Briefliy  described,  the  Worthington  Duplex,  as  constructed  for 
water  works,  consists  of  two  horizontal  tandem  compound  engines, 
each  of  which  is  connected  to  a  double-acting  water  plunger  by  a 

*  Since  these  figures  were  given  in  1884,  the  number  of  Water- Works  Engines  built 
by  Henry  R.  Worthington  has  been  increased  to  over  500,  having  an  aggregate  daily 
capacity  of  more  than  2,000,000,000  gallons. 


HISTORY  OF  THE   STEAM-ENGINE. 


CXXXIX 


continuation  of  the  high-pressure  piston  rod.  The  high-pressure 
cyhnder  is  usually  secured  in  the  front  head  of  the  low-pressure, 
the  latter  having  two  piston  rods  passing  through  long,  sleeved 


\ 


i     K 


stuffing-boxes  outside  the  high-pressure,  and  keyed  to  a  cross-head, 
which  has  also  the  high-pressure  piston  and.  plunger  rod  secured  to 
it.     The  steam  and  water  ends  of  the  machine  are  connected  by 


10 


Cxl  HISTORY   OF  THE   STEAM-ENGINE. 

turned  wrought-iron  cradle  bars,  as  they  are  termed,  which  make  a 
light  and  strong  connection.  From  the  cross-head  suitable  links 
operate  bell-cranks,  which  work  two  single-acting  vertical  air- 
pumps  for  each  engine.  These  bell-cranks  also  give  motion  to  the 
steam-distribution  valves,  which  are  slides  working  over  double 
ports ;  and  the  valve  for  one  side  (as  it  is  termed),  or  one  engine, 
strictly  speaking,  is  worked  by  the  bell-crank  of  the  other,  which 
enables  an  almost  constant  flow  of  water  to  be  maintained  in  the 
discharge  pipe.  The  water  valves  are  simple  rubber  disks  working 
over  brass  gratings,  and  closed  by  weights  or  springs.  Mr.  Worth- 
ington  is  entitled  to  the  credit  of  having  introduced  multiple  valves 
for  pumps.  The  later  Duplex  Engines  are  provided  with  cut-off 
valves,  independent  of  the  main  slides." 

The  terms  "High  Duty  "  and  "Low  Duty,"  as  applied  to  pumping 
engines,  are  used  mainly  to  distinguish  between  two  different  grades 
of  performance  with  reference  to  the  consumption  of  fuel.  In  sub- 
mitting propositions  for  furnishing  pumping  machinery  for  water- 
works, "  Low  Duty "  is,  generally  speaking,  held  to  comprise  en- 
:gines  upon  which  a  guarantee  of  duty  is  made  of  from  fifty  million 
ito  seventy  million  pounds  of  water  raised  one  foot  for  each  one 
(hundred  pounds  of  coal  burned.  "  High  Duty"  comprises  engines 
of  a  guaranteed  duty  of  from  ninety-five  millions  to  one  hundred 
and  ten  millions,  and  slightly  above.  All  other  things  being  equal, 
the  great  object  in  view  in  pumping  water  is  to  do  the  work  with 
the  least  practicable  consumption  of  fuel,  which  in  turn  simply 
means  the  least  possible  steam  used  by  the  engine.  The  most 
steam  is  used  by  a  pumping  engine  when  the  steam  follows  the 
pistons  from  the  beginning  to  the  end  of  their  stroke  without  any 
expansion  whatever.  The  least  steam  would  be  used  when  the 
inlet  valves  close,  and  are  caused  to  "  cut-off"  the  steam  at  the 
earliest  point  in  the  stroke  consistent  with  surrounding  conditions. 
Steam  following  the  piston  "full  stroke"  means  the  largest  con- 
sumption in  proportion  to  work  done.  Theoretically,  the  highest 
practicable  expansion  of  steam  means  the  greatest  economy.  The 
load  upon,  or  resistance  to,  a  pumping  engine  is  uniform,  and  there- 
fore the  propulsive  energy  of  the  machine  must  be  practically  uni- 
form, either  directly  by  virtue  of  the  action  of  steam  upon  the  pis- 
tons, or.  if.  the  .impialse., of  .the.  steam  is  variable,  its  excesses  and 


HISTORY  OF  THE  STEAM-ENGINE.  cxH 

deficiencies  must  be  made  good  by  the  mechanism  of  the  engine 
itself. 

The  Worthington  Duplex  Pumping  Engine,  although  so  widely- 
used  in  water-works  stations  for  the  past  thirty  years,  was,  owing  to 
peculiarities  not  necessary  now  to  discuss,  comparatively  limited  in 
its  capabilities  of  expanding  steam.  This  limited  steam  expansion 
relegates  the  Worthington  engine  of  the  past  to  the  class  of  "  low 
duty  "  machinery  of  to-day.  In  expanding  steam  to  an  extent  that 
will  secure  a  duty  of  one  hundred  millions  of  foot-pounds,  the  vari- 
able impulse  of  the  steam  during  the  piston's  stroke  makes  impera- 
tive the  demand  for  some  means  for  reducing  the  wide  variations  of 
steam  pressure  to  a  uniform  level.  The  problem  presenting  itself  is 
this :  At  the  beginning  of  the  stroke  the  impulse  of  the  steam  upon 
the  pistons  is  far  in  excess  of  that  demanded  for  moving  the  load ; 
at  the  terminus  of  the  stroke  the  impulse  of  the  steam  is  very  much 
less  than  what  is  required;  the  mean  pressure  during  the  stroke  is 
sufficient,  but  the  inequalities  must  be  instantly  equalized  when 
they  occur,  or  else  the  engine  will  start  with  a  violent  plunge,  and 
stop  short  of  the  end  of  its  stroke  at  a  point  where  the  driving  forces 
sink  below  what  is  demanded  by  the  resistance.  In  the  crank  and 
fly-wheel  engine  this  equalizing  effect  is  brought  about  by  a  ponder- 
ous fly-wheel,  which  absorbs  by  its  inertia  the  excess  of  energy 
at  the  beginning  of  the  stroke,  and  gives  it  out  at  the  end.  In 
other  words,  the  steam  impulse  upon  the  pistons  in  excess 
of  what  is  actually  required  to  move  the  load  at  the  beginning 
of  the  stroke,  is  expended  in  inertia  in  trymg  to  increase 
the  speed  of  the  fly-wheel ;  while  near  the  end  of  the  stroke, 
when  the  expansion  of  the  steam  in  the  cylinders  carries  the 
pressure  below  a  point  that  will  balance  the  resistance,  the  load 
is  moved  along  by  the  momentum  of  the  fly-wheel,  the  result  being 
that  the  steam  action  is  made  uniform  through  the  medium  of  the 
fly-wheel. 

In  the  Worthington  High  Duty  Engine  the  same  effects  of  high 
steam  expansion  are  obtained,  but  the  uniform  distribution  of  the 
steam  pressure  is  secured  by  an  entirely  different  method,  much 
simpler  and  more  effective,  and  embracing  none  of  the  objections  of 
the  fly-wheel,  and  presenting  many  positive  advantages. 

Expansion  by  means  of  compound  cylinders  alone  had  apparently 
been  carried  in  this  engine  to  its  practical  economic  limit,  with  such 


Cxlii  HISTORY  OF  THE  STEAM-ENGINE. 

Steam  pressure  as  is  usually  employed.  What  remained  to  be  gained 
from  it  further  could  be  secured  only  at  the  expense  of  certain  fea- 
tures of  construction  that  were  most  desirable  to  retain. 

Some  means  were  therefore  to  be  devised  by  which  the  gain  in 
efficiency,  due  to  cutting  off  and  expanding  the  steam  in  each 
cylinder  by  itself,  could  be  secured.  To  accomplish  this  through 
the  usual  medium  of  a  fly-wheel,  or  other  device  wherein  the 
momentum  of  a  moving  mass  is  utilized  for  the  storing  and  impart- 
ing of  energy,  would  be  to  rob  the  engine  at  once  of  those  distin- 
guishing characteristics  and  advantages  that  had  given  it  its  reputa- 
tion. To  make  this  change,  in  short,  would  be  to  abandon  entirely 
the  Duplex  principle. 

A  better  method  suggested  itself,  and  one  that  has  proved  emi- 
nently successful.  By  means  of  a  most  simple  attachment,  greatly 
increased  economy  in  running  ha.s  been  secured,  while,  so  far  as  its 
construction  or  the  quality  of  its  action  is  concerned,  the  engine  is 
left  unchanged. 

This  improvement  marks  a  most  important  and  radical  advance 
in  the  position  and  history  of  the  direct-acting  engine.  It  lifts  it  at 
once  from  the  plane  of  a  low  duty  engine  and  places  it  alongside, 
and  perhaps  in  advance  of,  such  engines  as  have  attained  the  high- 
est duties  yet  recorded.  Instead  of  the  engine  being  confined,  as 
heretofore,  to  an  expansion  of  steam  due  to  the  relative  areas  of  the 
cylinders,  it  can  now  be  run  at  such  ratio  as  is  found  to  be  the 
most  economical.  In  other  words,  any  point  of  cut-off  in  its  cylin- 
ders may  be  used. 

The  attachment  is  shown  in  the  illustrations  on  page  cxliii. 

It  consists,  briefly,  of  two  small  oscillating  cylinders  attached  to 
an  extension  of  the  plunger  rod  of  the  engine,  preferably  beyond 
the  water  end.  These  cylinders  and  their  connecting  pipes  are  filled 
with  water  or  other  liquid,  and  connected,  through  the  medium  of 
an  accumulator,  with  the  water  in  the  force-main  of  the  pump.  By 
this  means  a  pressure  on  the  pistons  in  these  cylinders  is  maintained 
exactly  equal  to,  or  in  proportion  to,  that  in  the  force-main.  These 
pistons  act  in  such  a  way  with  respect  to  the  motion  of  the  engine 
as  to  resist  its  advance  at  the  commencement  of  the  stroke,  and 
assist  it  at  the  end,  the  water  in  the  force-main  meanwhile  exerting 
upon  them  a  constant  pressure  at  each  point  of  the  stroke. 

The  two  cylinders  act  in  concert,  and  being  placed  directly  op- 


HISTORY  OF   THE   STEAM-ENGINE. 


cxHii 


posite  each  other,  reheve  the  cross-head  to  which  they  are  attached, 
of  any  shding  frictional  resistance,  and  the  engine  of  any  lateral 
strain. 

By  alternately  taking  up  and  exerting  power  through  the  differ- 
ence in  the  angle  at  which  their  force  is  applied  with  respect  to  the 
line  of  motion  of  the  plunger  rod,  these  two  cylinders,  in  effect,  per- 
form  the  functions  of  a  fly-wheel,  but  with  the  important  mechanical 
difference  that  they  utilize  the  pressure  in  the  force-main  instead  of 
the  energy  of  momentum.     Whatever  pressure  is  in  the  force-main 


THE   WORTHINGTON    HIGH    DUTY    PUMPING   ENGINE. 
Sectional  view. 


is  directly  communicated  to  the  compensating  cylinders,  and  any 
variation  in  the  force-main  pressure  is  followed  instantly  by  a  corre- 
sponding variation  in  the  cylinder  pressure.  Thus  a  uniform  rela- 
tion is  maintained  between  the  load  on  the  pump  plungers  and  the 
work  performed  by  the  compensators. 

Their  action  is  readily  controlled,  and  their  power  is  automatically 
proportioned  to  the  work  to  be  overcome,  and  is  entirely  unaffected 
by  the  speed  of  the  engine.  The  same  amount  of  expansion  can  be 
obtained  in  the  same  engine  whether  running  at  a  piston  speed  of 
ten  feet  per  minute,  or  at  one  hundred  and  fifty.  This  latter  feature 
is  of  great  importance,  affecting  as  it  does  so  favorably  the  economy 


Cxliv  HISTORY   OF   THE   STEAM-ENGINE. 

of  the  engine  when  appHed  on  any  service  where  the  demand  is 
irregular  or  intermittent.. 

Its  economy  is  not  appreciably  affected  by  the  widest  differences 
in  its  speed,  as  the  rate  of  expansion  in  the  steam  cylinders  is  con- 
stant under  all  changes  in  the  rate  of  delivery  of  the  pump.  The 
engine  adapts  itself  exactly  to  the  load ;  as  the  pressure  in  the  com- 
pensating cylinders  varies  proportionally  with  the  pressure  in  the 
force-main,  the  result  is  a  uniform  propulsion  of  the  water  column 
and  an  absolute  control  of  the  speed  of  the  engine,  without  depend- 
ence being  had  upon  any  automatic  governor  or  other  complicated 
device.  Should  the  force-main  or  distributing-pipes  burst  from  any 
cause,  no  accident  can  occur  to  the  engine  itself,  as  the  loss  of  pres- 
sure in  the  main  results  in  a  corresponding  loss  of  power  in  the 
compensating  cylinders,  until,  when  the  pressure  is  entirely  with- 
drawn from  them,  the  engine  is  unable  to  complete  its  strokes. 

The  work  of  the  compensating  cylinders  can,  at  the  will  of  the 
attendant,  be  thrown  on  or  off  the  engine  instantaneously.  Should 
they  or  the  cut-off  mechanism  become  in  any  way  disarranged,  or 
require  overhauling  or  repairs,  they  can  be  quickly  disconnected 
from  the  engine,  which  can  then  be  run  as  economically  and  satis- 
factorily as  though  originally  constructed  without  them. 

Where  the  most  economic  results  are  desired,  the  low-pressure  as 
well  the  high-pressure  cylinders  are  provided  with  cut-off  valves. 
These  consist  of  semi-rotating  circular  slide-valves  placed  in  the 
admission  ports  of  the  cylinders,  and  operated  by  means  of  the 
direct  connections  illustrated  in  the  engravings.  As  will  be  seen, 
their  action  is  secured  without  the  use  of  any  eccentrics,  gears  or 
cams.  When  the  point  of  cut-off  has  been  once  fixed,  it  need  never 
be  altered. 

Worthington  engines,  with  this  attachment,  have  been  fully  tested 
under  all  the  conditions  to  be  met  with  in  actual  practice,  and  have 
achieved  as  high  a  duty  as  has  heretofore  been  secured  by  an  engine 
of  any  other  type.  A  duty  of  one  hundred  million  (100,000,000) 
foot-pounds,  with  the  consumption  of  one  hundred  pounds  of  coal, 
can  be  considerably  exceeded  with  an  engine  developing  less  than 
one  hundred  horse-power. 

"Vertical  Direct-acting  Pattern." 
The  illustration  represents  a  Worthington  Vertical  Direct-acting 


HISTORY  OF  THE   STEAM-ENGINE. 


cxlv 


Pumping  Engine,  with  double-acting  outside  packed  plungers.  It 
involves  precisely  the  same  principles  of  construction  as  the  regular 
horizontal  engine,  excepting  the  balancing  device,  which  exactly 


THE   WORTHINGTON    VERTICAL    HIGH    DUTY    PUMPING   ENGINE. 

balances  the  weight  of  the  moving  parts.  Two  double-acting  ver- 
tical plunger  pumps  are  securely  bolted  to  the  foundations,  which 
in  turn  support  the  superstructure  to  which  is  secured  the  low- 


cxlvi  HISTORY  OF  THE  STEAM-ENGINE. 

pressure  cylinders.  Above  these  cylinders  extends  suitable  framing 
for  attaching  the  high-pressure  cylinders,  and  in  this  framing,  be- 
tween the  high  and  low-pressure  cylinders,  are  located  the  bearings 
for  the  compensating  cylinders  of  the  High  Duty  Attachment. 
This  design  embodies  all  the  essential  features  of  the  ordinary 
Worthington  engine,  modified  only  to  an  extent  sufficient  to  meet 
the  conditions  imposed  by  the  vertical  position  of  the  machinery. 
The  distance  between  the  pumps  proper  and  the  steam-end  of  the 
machine  can  be  varied  to  suit  any  demand  necessary  to  comply 
with  the  situation  as  regards  rise  and  fall  of  the  water  supply,  at 
the  same  time  keeping  the  steam  part  of  the  engine  above  high- 
water  mark.  The  steam  cylinders  can  be  placed  at  a  point  high 
enough  to  prevent  their  being  flooded  by  a  rise  of  water,  and  at  the 
same  time,  the  pumps,  or  water-end  of  the  engine,  may  be  placed 
low  enough  to  be  within  easy  suction  lift  when  the  source  of  supply 
has  fallen  to  its  lowest  stage.  This  form  of  the  Worthington  High 
Duty  Engine  is  applicable  to  the  variable  service  demanded  in  cities 
and  towns  situated  on  the  western  rivers.  The  steam  expansion, 
pump  action,  work  of  the  compensators,  and  all  of  the  various 
features  of  the  horizontal  High  Duty  Engine  will  be  found  com- 
pletely carried  out  in  these  Vertical  Engines.  Three  of  these 
engines,  as  shown  in  the  illustration,  each  having  a  daily  capacity 
of  10,000,000  gallons,  have  been  built  for  the  Artesian  Water  Com- 
pany of  Memphis,  Tenn.,  and  are  now  in  successful  operation.  Two 
engines  of  practically  the  same  type,  each  having  a  daily  capacity 
of  12,500,000  gallons,  have  been  built  for  the  city  of  Cincinnati. 
A  Worthington  Direct  Acting  Vertical  Pumping  Engine  has  also 
been  furnished  for  use  at  the  new  St.  Clair  Tunnel.  This  engine 
has  a  daily  capacity  of  5,000,000  gallons,  and  its  water-end  is 
placed  at  a  distance  of  125  feet  below  the  steam  cylinders. 

This  general  type  of  engine  is  also  made  with  inside  plungers 
working  through  composition  sleeves,  and  embodies  all  of  the 
essential  features  of  the  above  engine,  being  modified  only  in  such 
unimportant  respects   as   pertain  to   the   change   in  the    form   of 

plungers. 

"Vertical  Beam  Pattern." 

An  outline  engraving  of  the  Vertical  Water- Works  Beam  Engine 
is  shown  on  page  cxlvii.  This  type  of  the  Worthington  engine  also 
embodies  all  the  essential  features  of  the  regular  horizontal  machine. 


HISTORY   OF  THE   STEAM-ENGINE. 


cxlvii 


It  is  made  with  four  single-acting  outside  packed  water  plungers, 
one  plunger  directly  beneath  each  steam  cylinder,  the  connections 
between  the  steam  pistons  and  the  plungers  being  made  direct  and 
rigid.  Four  single-acting  water-cylinders  are  secured  to  the  founda- 
tions below,  and  two  strong,  heavy  bed-plates  are  supported  by  and 
secured  to  the  walls  of  the  pump-pit  or  foundations  above,  as  shown. 


VERTICAL   WATER-WORKS    BEAM    ENGINE. 


Rigid  connections,  or  distance-bars,  extend  from  the  pump  cylinders 
to  the  under  side  of  the  bed-plates,  thus  making  the  engine  entirely 
self-contained  as  far  as  the  working  strains  are  concerned.  The 
working  beams  are  supported  in  centre  bearings,  bolted  to  the  bed- 
plates, and  are  connected  at  their  ends  to  cross-heads  attached  to 
the  piston  rods  beneath  the  steam  cylinders.     The  high  duty  com- 


cxlviii  HISTORY   OF   THE   STEAM-ENGINE. 

pensating  cylinders  are  supported  in  pillow-blocks  at  the  ends  of 
the  bed-plates,  engaging  with  the  ends  of  the  working  beams,  one 
cylinder  at  each  end  of  the  beam  so  arranged  as  to  give  a  direct 
effective  distribution  of  their  energy  in  equalizing  the  power  of  the 
engine,  and  concentrating  it  upon  each  plunger  in  succession.  The 
engine  is,  naturally,  perfectly  and  completely  balanced  by  virtue  of 
its  design  and  arrangement,  without  regard  to  its  height  or  distance 
between  the  steam  and  water  ends  of  the  machine.  As  already 
pointed  out,  this  form  of  the  Worthington  engine  can  be  readily 
adapted  to  places  where  the  water  from  which  the  pumps  draw 
their  supply  is  liable  to  wide  variations  of  level.  At  the  lowest 
stages  of  the  water  the  suction  lift  is  from  twelve  to  fifteen  feet, 
while  in  time  of  flood  the  water  level  is  many  feet  above  the  pumps, 
although  the  steam  cylinders  and  working  parts  are  out  of  reach  of 
overflow.  Both  of  the  forms  herein  illustrated  of  the  Worthington 
Vertical  Pumping  Engine  can  be  adapted  to  be  run  either  high  or 
low  duty. 

The  Application  of  the  High  Duty  Engine  to  the  Direct 

Pressure  System. 

In  applying  the  High  Duty  Engine  to  the  direct  system  of  water 
^supply,  it  has  been  provided  with  ready  means  for  quickly  increas- 
ing its  power  so  as  to  meet  promptly  and  effectively  the  demands 
of  fire  service.  The  arrangement  employed  is  simple  and  complete, 
and  involves  only  the  quick  and  convenient  adjustment  of  the  cut- 
off valves  to  meet  any  fire  pressure  within  the  scope  of  the  engine, 
thus  suddenly  changing  the  machine  practically  to  the  regular  "low 
duty"  type. 

The  peculiar  automatic  operation  of  the  compensating  cylinders 
of  the  high  duty  attachment  is  most  clearly  illustrated  when  the 
engine  is  working  under  the  direct  system  of  water  supply.  If  the 
water  pressure  increases  slightly,  and  so  offers  more  resistance  to 
the  plungers,  this  very  increase  of  load  upon  the  engine  produces  a 
corresponding  increase  in  the  power  of  the  compensators,  exactly 
meeting  the  additional  demand  for  power  to  produce  a  full  stroke; 
while,  if  a  fall  of  pressure  occurs  and  the  plungers  should  thereby 
become  somewhat  relieved  and  develop  a  tendency  to  excessive 
motion,  the  corresponding  loss  of  power  in  the  compensators  pre- 
cisely counteracts  all  inclination. to  wards  irregularity. 


HISTORY  OF  THE  STEAM-ENGINE.  cxlix 

Several  Worthington  High  Duty  Pumping  Engines  have  also 
been  constructed  for  the  United  Pipe  Lines  that  can  deliver 
25,000  barrels  of  oil  in  twenty-four  hours  against  a  pressure 
of  1,500  pounds  per  square  inch.  The  engine  made  by  this 
company  for  the.  Paris  Exhibition  of  1889  is  the  largest  direct- 
acting  pumping  engine  in  the  world.  It  has  41-inch  high-pres- 
sure steam  cylinders,  with  82-inch  low-pressure  steam  cylinders, 
driving  12-inch  double-acting  plungers,  and  is  supplied  with  steam 
at  a  pressure  of  about  100  pounds  per  square  inch.  The  High  Duty 
Attachment  on  this  engine  weighs  about  3,500  pounds,  and  when 
the  engine  is  running  under  sixteen  expansions  and  at  a  piston 
travel  of  sixty-five  feet  per  minute,  it  is  estimated  that  the  com- 
pensating cylinders  are  developing  an  energy  that  could  not  be 
imparted  by  a  fly-wheel  of  a  less  diameter  than  forty  feet  and 
weighing  four  hundred  thousand  pounds. 

Description  of  Indicator  Cards. 

The  Steam  Engine  Indicator  has  probably  been  the  most  useful 
and  important  means  ever  discovered  for  enabling  the  designing 
engineer  to  arrive  at  desirable  and  appropriate  proportions,  in  con- 
structing steam  engines.  By  its  use  the  action  of  the  forces  at  work 
in  a  steam  engine  is  clearly  exhibited,  not  only  of  the  steam  itself, 
or  in  a  pumping  engine  of  the  water  as  well,  but  also  all  the  various 
effects  of  inertia,  friction,  movement  of  the  reciprocating  parts,  etc., 
etc.  By  a  combination  of  different  diagrams  many  interesting  and 
instructive  results  are  obtained,  which  by  careful  study  will  point 
out  the  way  of  improvement,  or  reveal  the  otherwise  hidden  causes 
of  observed  effects,  thereby  enabling  the  designer  to  make  such 
modifications  here  or  there,  as  the  case  may  require,  in  the  attain- 
ment of  any  desired  results. 

As  an  illustration  of  the  precise,  automatic  and  uniform  effect  of 
the  high  duty  feature  of  the  Worthington  engine,  are  shown  some 
combinations  of  indicator  cards  on  pages  cl  and  cli. 

In  all  pumping  engines  there  are  two  completely  antagonistic 
elements  to  be  reconciled,  viz. :  an  elastic  expanding  vapor  at  one 
end,  and  an  inelastic  non-compressible  fluid  at  the  other.  In  moving 
the  fluid  an  effect  must  be  obtained  as  near  absolute  uniformity  as 
possible,  while,  to  secure  the  greatest  economy  of  steam  expansion, 
it  is  necessary  to  produce  the  widest  practicable  variation  of  pres- 


cl 


HISTORY  OF  THE  STEAM-ENGINE. 


sure  upon  the  steam  pistons.  It  is  obvious,  then,  that  some  means 
must  be  provided  within  the  engine  to  equaHze  these  widely  differ- 
ing demands,  and  the  completeness  with  which  the  compensating 

cylinders  of  the  Worthing- 
ton  High  Duty  Engine  meet 
these  requirements  is  plainly 
shown  by  considering  the 
steam  cards  from  the  engine 
in  conjunction  with  the  ac- 
tion of  the  compensating 
FIG.   I. — STEAM  CARDS.  Cylinders. 

Fig.  I  is  an  indicator  card  with  diagrams  from  both  high  and  low- 
pressure  cylinders ;  Fig.  2  is  a  card  from  the  water-end  or  pump  of 
the  same  engine ;  these  cards  being  taken  from  a  Worthington  five- 
million  gallon  engine  in  ser- 
vice,    running     regularly 
against    an     average    water 
pressure  of  107  lbs.     It  will 
be  observed  that  the  varia- 
FiG.  2. — WATER  CARD.  tion  of  pressure  in  the  steam 

cylinders,  as  is  always  the  case  where  high  expansion  is  employed, 
is  nearly  100  lbs.,  whereas  the  card  from  the  pump  is  practically  uni- 
form. Fig.  3  shows  the  high  and  low-pressure  diagrams  both 
reduced  to  a  single  diagram  based  upon  the  low-pressure  piston 

area,     which     shows     the 

actual   variation    in    steam 

propulsion    during   the 

stroke.     Fig.  4    represents 

the  water  card  reduced  to 

FIG.  3.  the  same   scale  as  Fig.  3^ 

and   indicates   the   absolute  uniformity   throughout   the  stroke,  in 

striking  contrast  to  the  wide  variation  shown  by  the  expanding 

steam  in  Fig.  3. 

As  explained  previously,  the  action  of  the  compensating  cylinders 

of  the   high    duty   attach- 
ment is,  in  effect,  to  resist 
the  steam  pistons  the  first 
FIG.  4.  half  of  the  stroke,  and  to 

help  them  drive  the  load  during  the  last  half  of  the  stroke.     Fig. 


HISTORY  OF  THE  STEAM-ENGINE. 


Cli 


5  shows  how  efficiently  they  perform  this  important  work.  The 
diagram  in  Fig.  5  is  formed 
by  overlaying  the  steam 
card  in  Fig.  3  with  a  curved 
line  representing  the  pres- 
sure exerted  by  the  com- 
pensators. The  shaded 
portion  of  the  diagram 
gives  the  net  effect  of  pro- 
pulsion derived  from  the 
steam  pressure  upon  the 
engine  pistons  in  conjunc- 
tio7z  with  the  action  of  the  ^I^-  "• 

compensators.  The  remarkable  uniformity  of  the  combined  ef- 
fort is  indicated  by  the  tieaidy  equal  width  of  the  shaded  portion 
of  the  diagram  throughout  the  stroke ;  and  to  present  a  still  closer 
comparison  between  the  propulsive  energy  of  the  engine  and  the 
demands  for  uniformity  made  by  the  water  card  (Fig.  4),  we  produce 
Fig.  6  by  overlaying  the  water  card  with  the  shaded  part  of  the 
diagram  in  Fig.  5. 

It  will  be  observed  that  the  propulsive  energy  indicated  in  Fig.  6  is 
slightly  above  the  water  card  during  nearly  the  whole  stroke,  just 
enough  to  cover  the  friction  of  the  engine.  At  the  end  of  the 
diagram  (to  the  right)  is  shown  how  the  momentum  of  the  moving 
parts  of  the  engine  assists  in  finishing  the  stroke,  until  they  are 
arrested  in  their  movement  by  the  cushioning  effect  produced  in 
the  steam  cylinders.  The  indicated  energy  of  the  steam  power  as 
controlled  and  distributed  by  the  high  duty  attachment,  showing  an 
almost  exact  coincidence  with  the  straight  line  forming  the  top  of 
the  water  card,  explains  v/hy  the  action  of  the  Worthington  High 
Duty  Engine  is  absolutely  smooth  and  noiseless. 


HIGHEST  SPEED  ATTAINED  BY  LOCOMOTIVES. 


ENGLAND — THE    HIGHEST    RAILROAD    SPEED    TILL   AUGUST  6,   l! 

An  Edinburgh  despatch  to  the  New  York  Times  says :  Flying 
Scotchman  has  been  beaten  by  the  West  Coast  Flyer.  When 
the  London  and  Northwestern,  or  West  Coast  Express,  ran  into 
Edinburgh  Station  at  5.52  this  evening,  it  broke  all  previous  records 
of  high  railroad  speed,  not  only  for  England,  but  in  the  railway 
world  in  general.  This  was  the  first  day  of  the  great  400-mile  race 
between  two  of  the  biggest  English  Companies,  and  the  faster  train 
of  the  two  traversed  the  greater  part  of  that  distance  at  a  speed  of  a 
mile  a  minute. 

Competition  between  the  Great  Northern  and  West  Coast  Com- 
panies began  to  grow  lively  a  year  ago,  when  the  former,  by  adding 
third-class  compartments  to  its  Edinburgh  limited  express,  took 
away  the  third-class  passengers  which  the  Northwestern  had 
hitherto  carried  on  trains  going  at  a  somewhat  slower  speed.  Since 
that  time  the  contest  for  Edinburgh  travel  has  been  active. 

For  the  summer  traffic,  which  is  always  very  large,  the  Great 
Northern  in  June  reduced  its  schedule  time  to  8^  hours.  The 
West  Coast  Line  met  this  figure  July  i.  Competition  in  England 
always  cuts  time  and  never  cuts  rates.  Two  weeks  ago  the  Great 
Northern  made  a  further  cut  to  8  hours  and  its  rival  followed  suit. 
Great  Northern  trains  began  running  in  on  the  new  schedule  last 
Wednesday,  but  the  West  Coast  did  not  begin  until  to-day.  As  the 
Flying  Scotchman  on  the  old  9-hour  schedule  was  the  fastest 
train  in  the  world,  the  interest  taken  in  to-day's  race  between  the 
two  trains,  when  both  Avere  sent  through  in  8  hours,  was  naturally 
great  in  railway  circles  and  everywhere  else. 

In  company  with  Assistant  Superintendent  Turnbull,  of  the  West 
Coast  Line,  and  William  Acworth,  raflway  expert  of  the  London 
Times,  I  entered  a  first-class  compartment  at  Euston  this  morning 
just  before  10  o'clock.  The  West  Coast  was  the  better  line  to  go 
by.  It  only  had  to  get  through  in  the  same  time  to  win,  as  its 
longer  route  compels  it  to  make  i  mile  per  hour  more  than  the 
clii 


HISTORY   OF   THE   STEAM-ENGINE.  cliii 

Scotchman.  The  2  trains  pulled  out  at  the  same  moment,  the 
Scotchman  from  Kings  Cross  and  the  West  Coast  from  Euston. 
Everybody  in  our  compartment  flourished  a  watch.  We  could  not 
time  the  rival  train,  but  we  were  sufficiently  interested  in  keeping 
view  of  our  own  iron  horse,  as  that  capable  animal  probably 
travelled  faster  than  any  locomotive  ever  did  before  for  a  continuous 
run.  The  engine  had  a  single  pair  of  driving-wheels,  7  feet  6  inches 
in  diameter,  and  weighed  27  tons.  It  burned  24  pounds  of  coal 
per  mile  during  the  run.  The  tender,  loaded,  weighed  25  tons. 
Behind  it  were  4  coaches  filled  with  passengers,  making  a  weight 
of  20  tons  each,  or  80  tons  in  all.  We  started  slowly.  The  run  to 
Tring  was  up-grade,  the  steepest  portion  being  a  rise  of  i  foot  in 
70.  This  distance,  31^  miles,  was  covered  in  40  minutes.  Once 
over  the  hill,  the  engineer  woke  up  and  began  to  show  his  mettle. 
The  speed  was  increased  steadily  until  our  hair  began  to  stand  on 
end.  Telegraph  poles  began  to  seem  like  fence  posts  and  the  road- 
side a  medley  of  objects  hard  to  distinguish.  We  knew  we  were 
going  over  60  miles  an  hour,  but  were  not  prepared  for  the  an- 
nouncement that  the  speed  was  72  miles.  Mile-post  after  mile-post 
was  registered  at  50  seconds  by  our  watches,  and  the  15  miles  from 
Tring  to  Bletchley  took  exactly  12  minutes  and  30  seconds.  With 
a  speed  varying  between  72  miles  and  that,  we  flew  over  the  flat 
land,  the  spirits  of  the  party  naturally  heightened  by  the  novel  expe- 
rience after  the  first  tendency  to  hang  on  to  something  wore  off. 

Fears  now  began  to  be  entertained  that  we  were  going  to  stop  at 
Rugby,  as  is  u>ual  with  this  train.  The  general  desire  was  to  keep 
straight  on  to  Crewe,  158  miles,  without  halt,  according  to  schedule, 
and  the  fears  of  a  stop  at  Rugby  arose  only  from  the  fact  that  we 
were  several  minutes  ahead  of  time.  Rugby  was  passed  without 
halt,  however,  the  82^  miles  from  Euston  having  been  done  in  92 
minutes.  The  same  speed  was  kept  up  and  Tamworth,  lOO  miles, 
was  reached  in  two  hours.  The  run  of  95  miles  from  Tring  to  Tam- 
worth was  made  in  lOO  minutes,  which  was  considered  pretty  good. 
From  Tamworth  to  Crewe  took  58  minutes  for  48  miles,  and  we 
ran  into  the  latter  station  at  12.58,  two  minutes  ahead  of  the  schedule 
time.  This  run  of  158  miles,  without  a  halt,  in  2  hours  and  58 
minutes,  is  the  longest  known  to  any  schedule,  being  12  miles 
longer  than  the  Fort  Wayne  and  Chicago  run.  Water  was,  of 
course,  taken  in  from  the  track. 


cliv  HISTORY   OF   THE   STEAM-ENGINE. 

At  Crewe  we  spent  five  minutes,  exchanging  our  single-wheel 
driver  for  a  32-ton  engine,  with  two  pairs  of  driving-wheels.  The 
moment  we  pulled  out  of  the  station  it  became  evident  that  the  en- 
gineer proposed  to  show  what  he  could  do.  The  landscape  began 
to  fly  by  us  at  an  unprecedented  rate,  and  watches  began  to  regis- 
ter from  48^  to  48  seconds  for  the  following  miles.  This  meant 
from  73^  to  75  miles  per  hour.     This  speed  was  kept  up  for  8  or 

10  miles,  when  the  engineer,  contented  with  his  spurt,  eased  down 
to  60  miles  an  hour.  From  Hartford  to  Warrington  we  ran  12^ 
miles  in  113^  minutes.     Warrington  to  Wigan,  12  miles,  we  did  in 

1 1  minutes.  The  engineer  was  allowed  58  minutes  to  make  the  run 
of  5 1  miles  from  Crewe  to  Preston,  but  he  cut  under  the  schedule 
and  ran  into  Preston  in  exactly  51  minutes,  an  average  of  a  mile  a 
minute  from  platform  to  platform. 

We  spent  20  minutes  at  Preston  for  luncheon,  leaving  there  .'it 
2.18.  Once  out  of  town  we  clapped  spurs  to  our  animals  and  rose 
to  'j'>y  miles  per  hour.  The  run  from  Preston  to  Oxenholme,  40 
miles,  was  made  in  42  minutes,  the  last  ten  miles  being  up  gradu. 
A  heavy  grade  of  75  feet  was  met  at  Teebay  Junction,  but  we  did 
the  5^  miles  to  Sharp  Summit  in  8^  minutes,  this  being  at  the 
altogether  miserable  run  of  37^  miles  per  hour.  Once  over  Sharp, 
however,  we  began  to  do  72  miles  an  hour  again,  and  flew  along 
down  grade  at  this  rate  for  lo  miles,  when  we  slowed  down  and 
lounged  along  at  the  comfortable  pace  of  60  miles.  A  little  rise 
caused  further  diminution,  but  the  31  miles,  from  Sharp  to  Carlisle, 
was  done  in  31  minutes.  At  Carlisle  10  minutes  were  spent  and 
the  engine  changed  for  another  with  one  pair  of  large  drivers.  As 
before,  this  was  an  engine  specially  constructed  and  which  was  ex- 
hibited in  the  Edinburgh  Exhibition  of  1886.  With  this  we  went 
to  Beattock,  39^  miles,  in  39  minutes,  now  having  rain  against  us 
and  a  wet  track.  From  Battock  the  lo-mile  climb  to  Summit,  on  a 
grade  one  in  eighty,  was  done  at  the  rate  of  445^  miles  per  hour. 
Over  the  Summit  the  speed  rose  to  ^y^/i  miles,  and  the  next  13^ 
miles  took  only  12  minutes.  The  24  miles  from  the  Summit  to 
Carstairs  was  done  in  22  minutes,  and  at  a  slightly  less  rate  than 
a  mile  a  minute  we  finished  the  275^  miles  to  Edinburgh.  We  ran 
into  the  station  at  5.52  o'clock,  8  minutes  under  the  schedule.  The 
lOl  miles  from  Carlisle  had  been  covered  in  104  minutes,  over  a 
pass  1,015  feet  high,  and  this  run  is  simply  unprecedented  in  rail- 
way annals. 


HISTORY  OF  THE   STEAM-ENGINE.  ^i^ 

The  entire  distance  covered  was  400  miles,  and  the  actual  time, 
including  stops,  was  7  hours  and  25  minutes,  an  average  of  53|f 
miles  per  hour.  This  has  never  been  approached  before  for  so  long 
a  run.  The  fastest  continuous  record  in  England  hitherto  was  that 
of  the  special  train  which  took  the  Prince  of  Wales  from  Liverpool 
to  London,  200  miles,  in  3  hours  and  59  minutes,  an  average  slightly 
over  57  miles. 

After  we  arrived  the  Flying  Scotchman  thundered  into  the  Wav- 
erly  station.  We  had  beaten  it,  however,  not  only  7  minutes  in 
time,  but  8  miles  in  distance,  and  this  8  miles  superiority  on  the 
West  Coast  will  continue  as  long  as  present  schedule  holds,  which 
will  be  for  several  months  at  least.  It  is  now  said  that  Great  North- 
ern will  cut  to  7^  hours.  I  do  not  think  it  likely,  however,  as 
there  is  a  large  conservative  party  among  the  directors  opposed  to 
any  faster  speed.  Consequently  the  West  Coast  train  will  bear  off 
the  palm  henceforth. 

Despite  the  fearful  speed,  the  journey  was  not  at  all  unpleasant. 
The  jostling  and  lateral  motion  seemed  no  greater  than  when  going 
at  an  ordinary  speed.  The  sight  from  the  windows  was  very  un- 
usual, however.  Trains  coming  at  full  speed  from  the  opposite  di- 
rection went  by  with  a  crash  like  a  volley  of  musketry  and  were 
indistinguishable  brown-colored  masses  seen  only  for  a  moment. 

A  short  tunnel  was  like  a  gas  jet,  suddenly  extinguished  and  sud- 
denly relighted,  the  eye  not  having  time  to  accustom  itself  to  the 
darkness.  Long  tunnels  were  passed  through  with  a  booming  roar 
and  a  continuous  shower  of  sparks.  Against  the  blackness  it  was 
quite  like  an  effect  in  fireworks.  There  was  no  more  danger  in  the 
trip  than  in  one  at  the  ordinary  speed,  and  the  only  noticeable  dif- 
ference was  a  slight  shakiness  of  the  legs  upon  getting  out.  All 
the  passengers  bore  the  trip  well  except  one  lady,  and  the  eight- 
hour  express,  which  will  continue  through  the  summer  months,  will 
undoubtedly  be  a  popular  train. 

\^From  the  PhUadelpkia  Evening  Telegraph,  August  8,  l888.] 

America's  speed  record. 

The  liveliest  interest  was  manifested  yesterday  by  railroad  men  in 

the  cable  account  of  the  race  between  the  Flying  Scotchman  and  the 

West  Coast  Flyer  from  London  to  Edinburgh,  in  which  400  miles 

were  covered  by  the  winner  in  7  hours  and  25  minutes.     This  was 

11 


^lyl  HISTORY   OF   THE   STEAM-ENGINE. 

an  average  of  something  over  53^  miles  an  hour.  There  was  a 
general  jogging  of  memories  and  overhauling  of  the  records  of  fast 
railroad  trains  on  American  lines.  And  much  comfort  was  found 
by  many  in  going  over  those  records.  For  they  show  that,  although 
the  British  and  French  roads  admitted  make  much  better  time 
habitually  than  is  made  on  any  of  the  American  lines,  some  aston- 
ishing and  sustained  rates  of  speed  have  been  attained  here,  when 
special  efforts  were  expended  with  that  end  in  view. 

The  best  run  on  record  in  this  country  which  can  be  fairly  com- 
pared with  the  English  run  was  made  over  the  West  Shore  Road 
from  Buffalo  to  New  York  on  July  9,  1885,  when  426  miles  were 
covered  in  7  hours  and  27  minutes.  Quite  a  large  number  of  rail- 
road men,  including  officials  of  the  Baltimore  and  Ohio,  Wabash, 
Grand  Trunk,  and  West  Shore  Roads  happened  at  Buffalo  together 
en  route  for  New  York.  It  was  decided  to  see  how  quickly  they 
could  move  over  the  new  road.  At  the  start  the  railroad  men  had 
their  watches  out,  and  soon  the  mile-posts  were  flying  past  every  43 
seconds.  That  speed  was  held  so  steadily  that  the  greater  part  of 
the  run  was  made  at  the  rate  of  45  seconds  to  the  mile,  or  from  70 
to  83  miles  an  hour.  From  East  Buffalo  to  Genesee  Junction,  61 
miles,  took  56  minutes;  from  East  Buffalo  to  Newark,  93.4  miles, 
97  minutes;  from  Alabama  to  Genesee  Junction,  36.3  miles,  30 
minutes.  The  97  minutes  to  Newark  included  stops  of  9  minutes, 
making  the  actual  running  time  for  the  93.4  miles  88  minutes. 
From  Newark  to  Frankfort,  where  the  conditions  for  running  were 
not  so  good  as  before,  the  run  of  108.3  miles  was  made  in  134 
minutes,  including  17  minutes  for  stops.  From  East  Buffalo  to 
Frankfort,  202  miles,  the  time  was  240  minutes,  of  which  35 
minutes  were  consumed  in  stops. 

On  the  New  York  Central  Road  a  newspaper  train  with  two  cars 
weighing  sixty  tons  hauled  into  Syracuse  Sunday  morning,  August 
8,  1886,  at  10  o'clock,  an  hour  late.  The  train  was  booked  to  go 
from  New  York  to  Buffalo  in  nine  and  one-half  hours.  Orders 
came  to  try  and  make  up  for  the  time  on  the  further  run  of  148.7 
miles  to  Buffalo.  John  W.  Cool,  one  of  the  best  engineers  on  the 
road,  mounted  his  cab  bound  to  obey  the  order.  He  started  out  at 
54^  miles  an  hour.  At  the  end  of  three  miles  his  speed  increased 
to  66  miles  an  hour,  and  then  to  74^.  He  stopped  at  Rochester 
for  water  and   slowed    up  after  passing  Crittenden.     His  average 


HISTORY   OF  THE   STEAM-ENGINE.  civil 

speed  from  Syracuse  to  Rochester  was  6^}^  miles  per  hour;  from 
Rochester  to  Buffalo,  63.72  miles  per  hour,  and  from  Syracuse  to 
Buffalo,  65.6  miles  an  hour.  The  run  of  148.7  miles  was  made  in 
136  minutes. 

The  most  remarkable  long-distance  run  on  record  was  when  the 
Jarrett-Palmer  combination  went  from  New  York  to  San  Francisco 
in  half  time,  or  three  and  one-half  days.  Their  train  left  the  Penn- 
sylvania station  in  Jersey  City  at  12.53  ^^  ^^^  morning  of  June  i, 
1876.  They  were  not  to  make  a  stop  until  they  reached  Pittsburg. 
An  engine  and  baggage-car,  on  the  approach  of  the  special  to  Har- 
risburg,  got  up  a  speed  of  about  50  miles  and  passed  mails  to  the 
special  by  running  along  an  adjoining  track  for  several  miles  while 
the  mail-bags  were  thrown  from  train  to  train.  The  run  to  Pitts- 
burg, 438^  miles,  took  10  hours  and  5  minutes,  an  average  of  43^ 
miles  an  hour,  notwithstanding  the  AUeghenies.  From  Pittsburg  to 
Chicago,  458,3  miles,  took  ii  hours  and  6  minutes,  an  average  of 
42,1  miles,  including  twenty-five  stops  and  four  changes  of  engines. 
From  Chicago  to  Council  Bluffs,  491  miles,  took  iij4  hours,  an 
average  of  42.6  miles,  although  there  was  a  record  for  part  of  this 
journey  of  62.2  miles.  Over  the  Union  Pacific  the  run  of  1032.8 
miles  from  Omaha  to  Ogden  was  made  in  24  hours  and  14  minutes, 
at  an  average  of  41  miles  and  a  maximum  of  72  miles  an  hour. 
The  brakes  became  worn  at  Ogden  and  hand-brakes  had  to  be  used, 
retarding  the  onward  journey  somewhat,  as  the  men  feared  that 
they  might  lose  control  of  the  train,  San  Francisco  was  safely 
reached  at  12.57  ^^  June  4th,  quite  in  time  for  the  dinner  that  had 
been  ordered  for  the  company  for  that  day.  The  last  stage  of  the 
journey  was  run  at  an  average  of  37  miles.  During  the  entire  run 
20  engines  were  used,  there  were  72  stops,  and  the  running  time  for 
3313^  miles  was  84  hours  and  17  minutes,  an  average  of  40  miles 
an  hour. 

On  the  Pennsylvania  Road  forty-five  miles  an  hour  is  not  uncom- 
mon, and  there  are  level  stretches  where  a  speed  of  a  mile  a  minute 
is  attained.  Samuel  Carpenter,  the  General  Agent  of  the  road, 
said  yesterday  that  if  there  was  any  need  of  making  time  to  com- 
pare with  the  new  English  schedule,  it  could  be  done.  On  the  New 
York  Central  Road  the  run  of  eighty  miles  from  Rochester  to 
Syracuse  has  been  made  in  eighty  minutes  when  it  was  necessary  to 
make  up  lost  time.   Assistant  Superintendent  Voorhees,  of  the  New 


clviii 


HISTORY    OP'   THE   STEAM-ENGINE. 


York  Central,  said  that  he  stood  ready  any  day  to  send  a  party  from 
New  York  to  Buffalo,  440  miles  over  that  road,  in  the  same  time 
made  by  the  English  racer  for  400  miles,  if  the  party  would  pay 
two  dollars  per  mile  to  get  there  in  seven  hours  and  twenty-five 
minutes. 

Professor  Arthur  T.  Hadley,  of  Yale,  when  interviewed  upon  the 
subject,  said  that  he  had  been  at  work  during  a  portion  of  the  day 
m  order  to  go  over  some  of  the  best  American  railroad  records. 
The  result  of  his  examination,  he  says,  shows  that  the  claim  made 
by  the  Englishmen  that  the  run  made  August  6th  between  Edin- 
burgh and  London  broke  all  previous  records  for  high  railroad 
speed  in  England  and  the  railroad  world  cannot  be  supported  by 
fact. 

THE   LIMIT   OF    SPEED. 

The  speed  of  locomotives  has  not  grown  with  their  weight  and 
size.  There  is  a  natural  law  which  stands  in  the  way  of  this.  If 
we  double  the  weight  on  the  driving  wheels  the  adhesion  and  con- 
sequent capacity  for  drawing  loads  is  also  doubled.  Reasoning  in 
an  analogous  way,  it  maybe  also  said  that  if  we  double  the  circum- 
ference of  the  wheels,  the  distance  that  they  will  travel  in  one  revo- 
lution, and  consequently  the  speed  of  the  engine,  will  be  in  like 
proportion.  But,  if  this  be  done,  it  will  require  twice  as  much 
power  to  turn  the  large  wheels  as  was  used  for  the  small  ones ;  and 
we  then  encounter  the  natural  law  that  the  resistance  increases  as 
the  square  of  the  speed,  and  probably  at  even  a  greater  ratio  at 
very  high  velocities.  At  60  miles  an  hour  the  resistance  of  a  train 
is  four  times  as  great  as  it  is  at  30  miles.  That  is,  the  pull  on  the 
draw-bar  of  the  engine  must  be  four  times  as  great  in  the  one  case 
as  the  other.  But  at  60  miles  an  hour  this  pull  must  be  exerted  for 
a  given  distance  in  half  the  time  that  it  is  at  30  miles,  so  that  the 
power  exerted  and  the  amount  of  steam  generated  in  a  given  period 
of  time  must  be  eight  times  as  great  in  the  one  case  as  the  other. 
This  means  that  the  capacity  of  the  boiler,  cylinders,  and  the  other 
parts,  must  be  greater,  with  a  corresponding  addition  to  the  weight 
of  the  machine.  Obviously,  if  the  weight  per  wheel  is  limited,  we 
soon  reach  a  point  at  which  the  size  of  the  driving  wheels  and  other 
parts  cannot  be  enlarged,  which  means  that  there  is  a  certain  pro- 
portion of  wheels,  cylinder  and  boiler  which  gives  a  maximum 
speed. — M.  N.  Forney. 


HISTORY  OF  THE  STEAM-ENGINE.  ^Hx 

SPEED  ON  THE  RAIL. 

WILL  TRAINS  EVER  BE  RUN  AT  THE  RATE  OF  120  MILES  AN  HOUR 
OR  MORE?  OPINION  OF  EXPERT  WATKINS  OF  THE  SMITHSONIAN 
INSTITUTION,    WASHINGTON,  C.  D. 

September  lo,  1890. 

"  My  opinion  is  that  the  speed  limit  of  the  locomotive  engine  has 
been  reached  with  the  present  gauge  of  track  and  diameter  of  driv- 
ing-wheel," said  Expert  Watkins,  at  the  National  Museum,  to  a 
Washington  Star  reporter.  "  I  have  been  given  to  understand  on 
very  credible  authority  that  an  engine  on  one  road  has  already  made 
a  record  of  100  miles  an  hour — of  course,  over  a  very  short  dis- 
tance of  perfectly  straight  and  level  track.  If  that  is  to  be  beaten, 
it  will  only  be  done  by  mcreasing  the  size  of  the  boiler,  to  begin 
with.  To  get  a  greater  capacity  of  boiler  ir  will  be  necessary  to 
widen  the  locomotive,  and  therefore  the  track.  If  the  speed  of  any- 
thing like  120  miles  an  hour  is  to  be  attained  in  the  future,  the 
track  must  be  widened,  not  by  inches,  but  by  feet,  and  the  size  of 
the  driving-wheel  proportionately.  Naturally  the  question  of  safety 
is  the  first  one  brought  up  in  connection  with  a  discussion  on  this 
subject,  and  it  is  asked.  Can  trains  be  run  with  as  much  security  to 
life  and  limb  at  120  miles  an  hour  as  at  50?  My  answer  to  that 
is :  No.  Take  a  given  stretch  of  track,  in  perfect  condition,  with 
nothing  in  the  way,  and  a  train  is  more  likely  to  run  off  the  rail 
when  going  at  150  miles  an  hour  than  when  travelling  at  60.  But 
such  ideal  conditions  are  not  usually  found  in  railroading.  You 
must  consider  that  there  are  such  things  as  frogs  and  switches, 
which  get  out  of  order  or  misplaced,  as  well  as  a  multitude  of  other 
things,  more  difficult  to  look  out  for  the  more  rapidly  trains  are 
going.  Most  important  to  think  of,  too,  is  the  fact  that  if  an  acci- 
dent does  occur  the  train  that  meets  with  it  is  going  to  suffer  in 
proportion  to  the  speed  at  which  it  is  going  at  the  moment  of  in- 
terruption. Two  trains,  each  going  at  the  rate  of  120  miles  an 
hour  and  coming  into  collision,  would  quickly  be  reduced  to  kind- 
ling wood,  if  not  toothpicks. 

"Another  thing  worth  inquiring  about  is  the  number  of  men  that 
are  going  to  be  required  to  run  one  of  these  engines  of  the  future 
that  are  to  travel  120  miles  an  hour.  Jump  on  board  of  one  of  the 
fast-ffying  locomotives  at  Jersey  City  that  carries  you  to  Philadel- 
phia at  the  rate  of  nearly  a  mile  a  minute.  Do  nothing  but  watch 
the  signals  as  you  pass  with  lightning  speed  through  city  after  city 
at  grade  and  across  railway  after  railway  intercepting.     You  will 


clx  HISTORY  OF  THE  STEAM-ENGINE. 

find  that  it  takes  about  all  your  time  to  catch  them.  How  much 
leisure  has  the  engineer,  then,  to  look  after  his  steam  gauge  and 
water  gauge,  to  see  to  his  air  brake,  to  make  sure  that  every  part 
of  his  mighty  machine  is  in  order,  to  keep  in  touch  with  the  train- 
despatcher's  office  and  to  identify  any  extra  trains  as  they  pass  him, 
so  that  no  mistake  shall  be  made  ?  So  tremendous  is  the  strain 
upon  this  man's  nerves  that  as  a  measure  of  economy  the  company 
only  permits  him  to  work  four  days  each  week,  and  he  spends  the 
remaining  three  in  resting  and  bracing  up  for  further  contests  with 
space  and  time. 

"  Trains  in  England,  on  an  average,  run  faster  than  in  this  coun- 
try. Their  cars  or  carriages  are  not  nearly  so  heavy  as  ours ;  they 
have  not  nearly  so  many  heavy  grades  and  sharp  curves,  and  the 
law  gives  the  railway  exclusive  rights  over  their  tracks,  the  in- 
fringement of  which  is  punished  by  fine  and  imprisonment.  In 
England  one  person  out  of  every  2,250,000  people  carried  is  killed. 
To  ride  on  the  railways  in  France  is  a  great  deal  more  dangerous, 
inasmuch  as  one  out  of  every  2,000,000  passengers  is  killed.  Bel- 
gium is  much  safer  than  England  in  this  respect;  only  bne  out  of 
every  9,000,000  is  killed  on  its  roads.  Safest  of  all  by  far  are  the 
railways  of  Prussia,  which  only  kill  one  out  of  every  21,500,000 
people  carried.  There  are  many  advocates  in  favor  of  making  our 
railroad  cars  much  lighter,  the  argument  being  that  it  is  absurd  to 
drag  a  whole  row  of  houses  over  the  rails  in  order  to  transport  a 
lot  of  comparatively  light  packages  in  the  shape  of  people.  But  it 
is  very  certain  that  heavy  cars  have  the  advantage  of  safety  in  pro- 
portion to  their  weight.  You  will  notice  that  the  passengers  in  the 
heavily-built  parlor  cars  always  get  off  with  very  much  less  damage 
in  an  accident  than  do  the  occupants  of  the  ordinary  cars,  which  are 
usually  telescoped  by  the  Pullman  or  Wagner  coaches.  Extra 
heavy  weight  to  draw  means  extra  expense  for  the  railway  com- 
panies, but  safety  for  the  passengers  they  carry  means  saving  of 
money  in  damages  in  these  days  when  juries  are  given  to  mulct- 
ing the  companies  severely  in  such  cases.  Of  course,  you  read 
in  the  newspapers  about  the  running  of  Boynton's  bicycle  en- 
gine at  Brighton  Beach  the  other  day  at  the  rate  of  a  mile  in  thirty- 
two  seconds,  or  112  miles  an  hour.  That  may  give  a  notion  of  the 
future  of  railroading  as  regards  speed,  but  I  am  not  myself  of  the 
opinion  that  the  bicycle  idea  will  work  any  revolution  in  the  busi- 
ness of  transportation  by  rail." 


HISTORY   OF   THE   STEAM-ENGINE.  cixi 


THE  SONG  OF   STEAM. 

[G.  W.  Cutter.     Bom  in  Cincinnati,  in  1818.     A  captain  in  the  United  States  army 
during  the  invasion  of  Mexico.] 

Harness  me  down  with  your  iron  bands, 

Be  sure  of  your  curb  and  rein  ; 
For  I  scorn  the  power  of  your  puny  hands. 

As  the  tempest  scorns  a  chain  ! 
How  I  laughed  as  I  lay  concealed  from  sight 

For  many  a  countless  hour, 
At  the  childish  boast  of  human  might, 

And  the  pride  of  human  power! 

When  I  saw  an  army  upon  the  land, 

A  navy  upon  the  seas, 
Creeping  along,  a  snail-like  band, 

Or  waiting  the  wayward  breeze  ; 
When  I  marked  the  peasant  fairly  reel 

With  the  toil  which  he  faintly  bore, 
As  he  feebly  turned  the  tardy  wheel. 

Or  tugged  at  the  weary  oar — 

When  I  measured  the  panting  courser's  speed, 

The  flight  of  the  courier-dove. 
As  they  bore  the  law  a  king  decreed, 

Or  the  lines  of  impatient  love, 
I  could  not  but  think  how  the  world  would  feel 

As  these  were  outstripped  afar, 
When  I  should  be  bound  to  the  rushing  keel, 

Or  chained  to  the  flying  car ! 

Ha !  ha !  ha !  they  found  me  at  last ; 

They  invited  me  forth  at  length ; 
And  I  rushed  to  my  throne  with  a  thunder-blast, 

And  laughed  in  my  iron  strength  ! 


Clxii  HISTORY   OF   THE   STEAM-ENGINE. 

Oh !  then  ye  saw  a  wondrous  change 

On  the  earth  and  ocean  wide ; 
Where  now  my  fiery  armies  range, 

Nor  wait  for  wind  or  tide. 

Hurrah  !  hurrah !  the  waters  o'er 

The  mountain's  steep  decline ; 
Time — space — have  yielded  to  my  power; 

The  world — the  world  is  mine ! 
The  rivers  the  sun  hath  earliest  blest, 

Or  those  where  his  beams  decline, 
The  giant  streams  of  the  queenly  West, 

And  the  Orient  floods  divine. 

The  ocean  pales  where'er  I  sweep, 

To  hear  my  strength  rejoice ! 
And  the  monsters  of  the  briny  deep 

Cower,  trembling  at  my  voice. 
I  carry  the  wealth  to  the  lord  of  earth, 

The  thoughts  of  his  god-like  mind ; 
The  wind  lags  after  my  flying  forth. 

The  lightning  is  left  behind. 

In  the  darksome  depths  of  the  fathomless  mine. 

My  tireless  arm  doth  play  ; 
Where  the  rocks  never  saw  the  sun's  decline. 

Or  the  dawn  of  the  glorious  day. 
I  bring  earth's  glittering  jewels  up 

From  the  hidden  cave  below, 
And  I  make  the  fountain's  granite  cup 

With  a  crystal  gush  o'erflow. 

I  blow  the  bellows,  I  forge  the  steel. 

In  all  the  shops  of  trade ; 
I  hammer  the  ore  and  turn  the  wheel, 

Where  my  arms  of  strength  are  made. 
I  manage  the  furnace,  the  mill,  the  mint; 

I  carry,  I  spin,  I  weave ; 
And  all  my  doings  I  put  into  print 

On  every  Saturday  eve. 


MODERN  STEAM  PRACTICE 

AND  ENGINEERING. 


COAL    AND    COAL-MINING. 

Coal  is  the  primary  source  of  our  commerce  and  manufactures, 
by  enabling  steam-power  and  machinery  to  be  produced  at  the 
most  economical  rate.  The  economical  importance  of  the  coal 
deposits  in  England  and  Scotland  is  much  enhanced  by  the  rich 
beds  of  iron  ore  found  in  their  associated  shales,  as  well  as  in  the 
contiguity  of  the  carboniferous  limestone  which  is  required  to  assist 
in  reducing  the  ore  to  a  metallic  state,  not  to  speak  of  the  lesser 
advantage  of  the  proximity  of  the  fire-clay,  which  furnishes  the 
only  material  for  building  blast-furnaces  capable  of  resisting  the 
heat  of  the  smelting  process.  The  varieties  of  coal  usually  met 
with  are  anthracite,  caking-coal,  cherry-coal,  splint-coal,  and 
cannel-coal. 

For  manufacturing  purposes  coals  are  generally  considered  to 
consist  of  two  parts — a  volatile  or  bituminous  portion,  and  a  sub- 
stance comparatively  fixed,  and  usually  known  by  the  name  of  coke. 
This  latter  form  of  coal  is  extensively  used  in  locomotive  engines 
on  railways,  in  consequence  of  its  yielding  no  smoke,  the  volatile 
matter,  or  that  which  forms  the  smoke  of  coal,  being. removed  by 
ignition.  As  the  bituminous  or  volatile  part  of  coal  yields  the  gas 
used  for  lighting,  it  has  been  found  that  the  heating  power  of  the 
coal  resides  in  the  coke,  and  no  heat  is  lost  by  first  extracting  the 
gas  from  coal  by  the  usual  methods  of  burning,  or  rather  distilling 
coal. 

Coal  is  deposited  in  beds  more  or  less  horizontal,  although  some- 
times by  movements  of  the  earth's  crust  their  position  has  become 
much  inclined.  The  great  coal-field  of  Britain,  which  is  composed 
of  numerous  subordinate  coal-fields,  crosses  the  island  in  a  diagonal 
direction,  the  south  boundary  line  extending  from  near  the  mouth 
of  the  river  H umber,  upon  the  east  coast  of  England,  to  the  south 


2  MODERN   STEAM    PRACTICE. 

part  of  the  Bristol  Channel  on  the  west  coast;  and  the  north  boun- 
dary line  extending  from  the  south  side  of  the  river  Tay  in  Scot- 
land, westward  by  the  south  side  of  the  Ochil  Hills,  to  near 
Dumbarton  upon  the  river  Clyde;  within  these  boundary  lines 
North  and  South  Wales  are  included.  This  area  is  about  260  miles 
in  length,  and  on  an  average  about  150  miles  in  breadth.  Coal 
also  occurs  in  other  formations  of  later  geological  age;  but  none  of 
these  later  deposits  equal  in  economical  importance  the  rich  stores 
of  the  carboniferous  system  in  our  island.  Beds  of  coal  are  found 
in  most  European  countries,  as  also  in  China,  India,  Australia, 
Japan,  and  Borneo;  but  the  coal-fields  of  the  United  States  of 
America  are  by  far  the  most  extensive  and  richest  in  the  world. 

Boring  in  search  of  coal  is  an  important  branch  of  mining.  In 
ordinary  practice  the  boring  plant  consists  of  shearlegs,  windlass, 
brake,  brace-head,  bore-rods,  cutting  tools,  &c.  Steam -engiiles 
specially  adapted  for  boring  have  also  been  devised.  A  very  simple 
method  with  hollow  rods  combined  with  a  force-pump  was  intro- 
duced by  M.  Fauvelle  in  1846. 

The  "troubles"  met  with  in  working  coal  are  various: — for 
example,  a  "want"  or  "nip"  is,  as  its  name  suggests,  a  part  of  the 
field  where  no  coal  exists,  or  only  in  a  very  thin  streak;  if  this 
streak  is  followed,  however,  the  coal  seam  will  again  be  found. 
"Dykes"  are  generally  of  whin,  projecting  from  below.  It  rarely 
happens  that  the  coal  is  either  elevated  or  depressed  by  this 
"  trouble,"  but  it  is  much  burned  and  rendered  useless  for  some 
yards  on  either  side.  A  "  step  "  or  "  fault "  is  a  dislocation,  some- 
times of  considerable  magnitude,  by  which  the  strata  are  elevated 
or  depressed  many  fathoms.  A  "  hitch  "  is  of  the  same  nature  as 
a  "step,"  but  on  a  smaller  scale.  A  whin  bed  is  perhaps  the  worst 
kind  of  "  trouble "  to  be  met  with,  as,  when  found  near  to  and 
parallel  with  a  coal-seam,  it  renders  the  entire  bed  useless.  When 
a  miner  meets  with  a  "  step "  or  a  "  hitch "  he  at  once  knows 
whether  it  is  an  "  up  throw  "  or  a  "  down  throw."  If  a  "  hitch  "  lies 
off  at  the  top,  by  following  the  rise  upwards  he  will  find  the  coal; 
if  off  at  the  bottom,  he  must  follow  the  dip  downwards.  Although 
it  is  both  annoying  and  expensive  to  meet  with  these  "  troubles," 
they  often  serve  useful  purposes:  "steps,"  for  instance,  sometimes 
elevate  the  coal  from  a  depth  that  would  be  difficult  to  reach  by 
ordinary  means  to  a  depth  of  comparatively  easy  working.  Again, 
when  a  coal-seam  is  nearly  cropping  out,  a  "step"  is  met  with 


COAL  AND   COAL-MINING.  3 

that  throws  it  down,  in  this  way  extending  the  field.  Again,  whin 
dykes  serve  the  purpose  of  dams,  and  prevent  water  passing  from 
one  "  waste  "  or  worked-out  space  to  another. 

It  is  also  of  importance  to  fix  on  the  best  position  and  form  for 
the  pits.  Where  much  water  may  be  expected,  the  best  form  for 
the  pit-shaft  is  circular,  so  that  the  water  met  with  in  sinking  may 
be  kept  back  by  tubbing;  that  is,  lining  the  shaft  with  suitable 
material,  such  as  stone,  timber,  or  cast-iron,  the  latter  being  pre- 
ferred. When  the  pressure  of  water  is  great,  sometimes  the  tub- 
bing is  formed  of  half  rings,  so  as  to  fit  the  shaft;  but  where  pumps 
and  brattices  interfere,  segments  of  cast-iron  are  used,  about  4  feet 
in  length  and  2  feet  in  height,  and  from  ^  of  an  inch  to  i  inch  in 
thickness.  The  segments  are  made  to  form  a  smooth  surface  in 
the  shaft,  and  they  are  fitted  to  each  other  by  means  of  flanges, 
3  to  4  inches  at  each  end,  and  the  spaces  between  the  segments 
are  filled  up  with  thin  deal.  Stone  tubbing  is  merely  common 
walling,  with  the  foundation  made  tight  by  means  of  grooves  cut 
in  the  stone,  the  joints  and  backing  being  filled  up  with  cement, 
which,  if  carefully  executed,  will  answer  for  light  purposes;  but  the 
success  of  this  method  of  tubbing  is  of  too  precarious  a  nature  to 
meet  with  general  application  for  important  works,  and  wood  or 
iron  is  preferred.  It  sometimes  happens  in  sinking  pits  that  all  the 
wells  and  springs  in  the  neighbourhood  are  drained  off,  but  this  evil 
may  be  prevented  by  tubbing  the  shaft. 

Some  pits  are  sunk  at  great  expense,  owing  to  the  nature  of  the 
strata  which  have  to  be  passed  through,  and  other  difficulties,  as, 
for  example,  a  heavy  flow  of  water.  Such  instances  occur  in  the 
north  of  England,  as  at  Pemberton's  Pit,  Monkwearmouth,  near 
Sunderland,  and  a  pit  at  Seaham  near  Durham,  which  is  300 
fathoms  deep  and  cost  the  enormous  sum  of  ;^  100,000.  Before  the 
steam-engine  was  introduced,  the  coal-pits  capable  of  drainage  with 
hydraulic  machinery  or  water-engines  were  comparatively  few  in 
number;  and  when  drained  by  wind-mills,  as  was  sometimes  the 
case,  the  pits  were  drowned  in  calm  weather.  The  driving  of  day 
levels  was  thus  a  primary  object  with  the  early  miner;  and  this 
system  of  draining  is  the  cheapest  where  circumstances  allow  of  its 
adoption.  The  day  levels  were  often  of  sufficient  dimensions  to 
admit  of  roads,  and  even  in  some  cases  of  canals,  being  formed  in 
them,  so  that  machinery  was  not  required.  In  modern  times,  how- 
ever, the  water  is  pumped  from  great  depths  by  steam  power,  the 


4  MODERN   STEAM   PRACTICE. 

single-acting  Cornish  pumping  engine,  having  a  beam  with  the 
steam  cylinder  at  one  end  and  plunger  or  force  pumps  at  the  other, 
being  extensively  used.  Sometimes  lift  or  bucket  pumps  are 
introduced,  while  in  other  cases  both  plunger  and  lift  are  combined 
in  a  single  barrel.  Some  of  these  engines  work  direct,  the  pump 
rods  being  attached  at  once  to  the  piston-rod  over  the  pit. 

The  deleterious  air  met  with  in  mines  is  of  two  kinds,  the  one 
being  heavier  and  the  other  lighter  than  atmospheric  air; — the 
natural  consequence  of  which  is  that  the  heavier  gas  rests  in  the 
lower  parts  of  the  mine,  while  the  lighter  ascends  to  the  higher 
parts.  The  heavier  is  carbonic  acid  gas,  known  to  the  miners  by 
the  names  of  "choke-damp,"  "black-damp,"  and  "stythe;"  the 
lighter  gas  is  carburetted  hydrogen,  commonly  called  "  fire-damp," 
or  inflammable  gas.  Where  the  former  gas  has  been  allowed  to 
accumulate  there  is  great  difficulty  in  getting  it  expelled.  In  coal 
mines  it  is  seldom  present  except  as  "after-damp,"  and  is  the 
result  of  a  preceding  explosion.  No  light  will  burn  in  this  gas. 
We  have  seen  a  fire-lamp,  with  about  3  cwt.  of  coal  in  full  blaze, 
burning  in  a  pit  where  choke-damp  filled  the  bottom,  as  completely 
extinguished  as  if  it  had  been  plunged  in  water.  At  times,  though 
seldom,  the  coal  has  been  known  to  catch  fire  in  mines,  and  burn 
for  years;  in  such  cases  carbonic  acid  gas  has  been  successfully 
applied  in  extinguishing  these  fires. 

Carburetted  hydrogen  or  "fire-damp,"  the  lighter  gas,  is  not 
explosive  until  mixed  with  atmospheric  air.  According  to  experi- 
ment, the  mixture  most  explosive  is  i  of  gas  to  6  of  atmospheric 
air;  when  it  is  i  to  14  a  candle  burns  in  it,  but  with  a  flame  much 
elongated.  Many  of  the  fearful  explosions  and  attendant  loss 
of  life  occasioned  by  this  gas  arise  from  carelessness.  Some 
obstruction  in  the  air  course  is  allowed  to  take  place,  a  door  has 
been  left  open  all  night,  or  a  miner  enters  his  room  with  a  safety- 
lamp  in  his  hand,  but  has  neglected  to  remove  the  open  lamp  from 
his  cap ;  even  some  of  the  miners  are  so  fool-hardy  as  to  light  their 
tobacco-pipes  by  drawing  the  flame  through  the  wire  gauze,  thus 
igniting  the  gas.  We  need  not  impress  upon  all  workmen  the  great 
danger  arising  from  such  carelessness. 

The  electric  light  is  being  experimented  with  at  present  as  an 
illuminating  medium  for  coal  workings.  The  great  difficulty  in 
fiery  mines  being  the  risk  of  explosion  arising  from  lights,  it 
becomes  an  important  matter  to  devise  methods  to  meet  this  danger. 


COAL  AND   COAL-MINING.  5 

The  Davy  lamp  does  not  emit  a  strong  light;  hence  if  it  can  be 
proved  that  the  electric  light  will  not  set  fire  to  the  inflammable 
gases  of  the  mines  in  the  event  of  accidental  breakage  of  the 
protecting  glass  globes,  its  intense  light  should  prove  very  valuable 
to  the  miner. 

It  has  been  found  by  experiment  that  the  presence  of  coal 
dust  in  the  workings  contributes  much  to  the  risk  of  explosions; 
and  it  seems  certain  that  if  3  per  cent,  of  gas  exists  in  the  air 
of  a  mine  which  is  thoroughly  mixed  with  coal  dust,  an  explosive 
mixture  is  formed.  Mines  should  have  at  least  two  shafts,  one 
of  which  serves  to  admit  the  pure  air,  while  the  foul  gases  escape 
by  the  other.  The  ascent  of  these  gases  is  facilitated  by  creating 
a  draught  by  means  of  a  furnace  at  the  bottom  of  one  of  the  shafts 
or  by  fans  driven  at  a  high  speed  placed  at  top.  This  shaft 
is  called  the  upcast  shaft;  the  downcast  shaft,  which  may  be  within 
a  few  yards  of  the  other,  allows  the  fresh  air  to  pass  down  to  the 
workings,  to  the  faces  of  which  it  is  directed  by  partitions  of  wood 
or  canvas  called  "  brattices."  The  air  in  its  circuit  below  will 
travel  several  miles. 

The  coal  lies  in  parallel  layers,  between  which  the  gas  exists  in 
a  highly  compressed  state.  In  order  to  detach  these  layers  with 
the  least  possible  danger,  it  is  usual  to  cut  through  them  endways, 
by  which  means  the  gas  is  allowed  to  make  its  escape  at  once  from 
a  considerable  portion  of  the  coal.  From  observation  of  some 
mines  it  is  sqen  that  discharge  of  fire-damp,  though  governed  by 
atmospheric  pressure,  takes  place  before  being  indicated  by  the 
barometer,  so  that,  as  an  indicator,  that  instrument  cannot  be  relied 
on.  As  before  said,  the  explosion  of  "fire-damp"  in  a  mine  results 
in  an  accumulation  of  the  dangerous  "  after-damp,"^  and  more  lives 
are  lost  by  it  than  by  the  explosion  itself.  It  has  the  appearance 
of  a  dense  misty  vapour,  and  resists  the  application  of  ventilation 
in  an  extraordinary  manner.  It  benumbs  the  faculties  and  deprives 
the  miner  of  all  presence  of  mind,  so  that,  instead  of  rushing  at 
once  to  the  pit  bottom,  if  he  has  escaped  the  fire,  he  gets  bewild- 
ered, and  a  deadly  lethargy  comes  over  him,  ending  in  sleep  from 
which  he  never  awakes.  It  is  rare  to  find  choke-damp  and  fire- 
damp in  the  same  workings,  or  if  they  do  occur  it  is  only  in  small 
quantities. 

*  A  mixture  of  carbonic  acid  and  other  products  of  the  combustion  of  the  carburetted 
hydrogen. 


MODERN    STEAM   PRACTICE. 


The  only  effectual  means  of  preventing  accidents  from  these 
gases  is  a  complete  system  of  ventilation  by  air-courses  through 
the  mine.  This  ventilation  is  maintained  either  by  the  natural  heat 
of  the  mine;  by  mechanical  appliances,  as  pumps,  fans,  or  pneu- 
matic screws — either  forcing  air  into  the  downcast  shaft  or  exhaust- 
ing it  from  the  upcast  shaft,  by  water  falling  constantly  down  the 
downcast,  or  by  furnaces  placed  at  the  bottom  of  the  upcast.  For- 
merly furnace  ventilation  was  considered  to  be  the  most  efficient 
and  reliable  mode  of  ventilating  very  deep  pits.  The  distance  of 
the  furnace  from  the  bottom  of  the  upcast  shaft  is  a  point  of  impor- 
tance, 30  to  40  yards  being  a  common  distance. 

Th^'  fins  used  for  ventilation  may  be  divided   into  two  kinds. 


Fig.  I.— Side  Elevation  of  Guibal  Fan.      a  a.  Rotating  Fan.     b.  Discharge  Orifice.     C,  Outlet. 

viz.  pump  and  centrifugal.  In  the  first  class  are  the  Struve,  Nixon, 
Lemielle,  and  Roots;  and  in  the  second  class  the  Guibal,  Rammell, 
Waddle,  and  Schiele.  Mechanical  ventilators  of  the  fan  descrip- 
tion appear  in  some  cases  to  effect  a  saving  of  about  50  per  cent 


COAL   AND   COAL -MINING.  7 

over  the  furnace  system,  and  the  useful  effect  of  a  good  fan  seems 
to  be  from  40  to  60  per  cent,  of  the  power  employed.  The  quan- 
tity of  air  discharged  varies  with  the  size  of  the  fan  and  the  speed 
of  rotation.  In  some  of  the  centrifugal  fans  of  about  16  feet 
diameter,  the  quantity  of  air  in  cubic  feet  per  minute  passed 
amounts  to  from  40,000  to  50,000,  and  in  larger  fans  of  30  to  50 
feet  diameter,  100,000  to  200,000  cubic  feet  per  minute  may  be 
discharged.  In  the  Schiele  fan  the  speed  is  very  high,  150  to  300 
revolutions  per  minute,  the  diameter  being  smaller  than  some  of 
the  other  forms,  such  as  the  Guibal,  which  is  generally  of  a  larger 
diameter  with  a  less  velocity  of  rotation,  say  about  90  revolutions 
per  minute.  An  engraving  of  the  Guibal  fan,  which  is  now  largely 
used,  is  shown  in  Fig.  i. 

As  a  general  rule  no  mine  should  have  a  ventilating  power  of 
less  than  lOO  cubic  feet  per  minute  for  each  man  and  boy  employed 
in  the  underground  passages,  and  in  mines  making  large  quantities 
of  fire-damp  a  ventilation  equal  to  from  200  to  600  cubic  feet  per 
minute  per  man  should  be  attained. 

The  common  methods  of  working  coal  in  this  country  are  "long- 
wall  "  and  "  stall  and  pillars,"  with  a  modification  of  the  latter  called 
"  ranees."  By  the  "  long-wall "  system  all  the  coal  is  excavated, 
and  it  is  the  most  profitable  way  of  working.  Before  starting  any 
coal  "  long-wall,"  however,  there  are  several  circumstances  to  be 
considered,  such  as  the  nature  of  the  roof,  the  property  that  might 
be  injured  by  the  subsidence  of  the  superincumbent  strata,  and  so 
on.  In  the  "stall  and  pillar"  system  there  is  a  great  sacrifice  of 
coal,  generally  about  one-third,  but  often  nearly  one-half;  this  plan, 
therefore,  should  never  be  adopted  if  the  coal  can  be  worked  "  long- 
wall."  Pillars  are  often  left  large  or  worked  in  "  ranees,"  with  the 
intention  of  being  afterwards  removed ;  but  this  plan  does  not 
always  succeed.  Large  as  the  pillars  may  be,  they  often  sink  into 
the  pavement  if  it  is  soft,  and  cause  a  "  creep,"  which  shatters  the 
coal,  besides  forcing  the  soft  pavement  up  to  the  roof  in  the  roads  and 
rooms  or  stalls,  and  the  contemplated  removal  of  the  pillars  is  thus 
frustrated.  The  edge  seams  of  coal  are  worked  "  long-wall "  in  some 
cases,  and  "stall  and  pillar"  in  others.  Instead  of  the  pits  being 
sunk  straight  down,  inclined  shafts  are  driven  through  the  bed  of 
coal,  with  rooms  branching  l.^*  from  either  side  of  the  incline,  and 
to  work  these  the  men  stand  on  the  coal  as  a  floor,  having  the  coal 
also  as  the  roof.     In  the  shaft,  instead  of  a  cage  and  slides,  there  is 


8  MODERN   STEAM   PRACTICE. 

a  tramway,  with  trucks  capable  of  holding  two  hutches  or  small 
waggons  in  each,  the  tramways  being  laid  double  in  order  to 
balance  the  engine,  one  truck  ascending  and  the  other  descending, 
as  in  ordinary  vertical  shafts.  These  trucks  have  likewise  boxes 
fitted  for  drawing  the  ^ater,  the  mechanism  for  doing  so  being 
self-acting. 

The  method  now  universally  adopted  for  bringing  the  coal  to  the 
surface  is  by  a  steam-engine  having  a  drum  on  which  the  wire  ropes 
are  wound,  the  drum  being  sheathed  with  wood ;  the  cages  or  frames 
for  holding  the  hutches  or  small  waggons  being  attached  to  the 
other  end  of  the  wire  ropes,  which  are  so  arranged  that  one  cage  is 
descending  with  an  empty  hutch,  and  the  other  ascending  with  a 
hutch  full  of  coal,  the  men  descending  and  ascending  in  like  manner. 
The  shaft  has  a  central  division  all  the  way  down,  formed  of  timber, 
to  which  are  attached  balks  of  the  same  material ;  balks  are  also 
fixed  to  each  side  of  the  shaft,  to  form  a  guide  for  the  cages,  the 
cage  or  iron  frame  having  guiding  pieces  fitted  to  it.  Many  ingeni- 
ous devices  have  been  adopted  to  disconnect  the  cage  from  the  rope 
in  case  of  over-winding,  or  to  prevent  the  cage  from  being  dashed 
to  the  bottom  should  the  rope  snap.  All  these  plans  consist  of 
mechanical  contrivances,  such  as  wedges,  clips,  eccentrics,  serrated 
and  arranged  with  springs  and  levers,  so  as  instantly  to  grip  the 
guides  in  the  pit,  and  thus  sustain  the  cage  until  the  defects  are 
made  good.  On  the  engine  shaft  is  fitted  a  worm  wheel  and  pinion, 
with  an  index,  so  that  the  engine  tenter — who  should  always  be  on 
the  look  out,  as  this  index  is  intended  to  point  out  the  approach  of 
the  cage  either  way — knows  when  to  stop  the  engine  at  the  top  or 
bottom.  All  modern  engines  are  fitted  with  the  link  motion  for 
actuating  the  slide  valve;  thus  the  man  in  charge  of  the  engine 
can  stop  and  reverse  instantly,  and  so  prevent  accidents  from  over- 
winding. 

A  variety  of  machines  have  been  introduced  for  cutting  and 
breaking  down  the  coal,  saving  the  practical  miner  much  hard 
labour.  These  consist  chiefly  in  an  arrangement  of  a  series  of 
cutters,  which  are  made  to  revolve  by  the  action  of  compressed  air 
or  steam ;  and  they  answer  in  certain  localities  where  the  seams  of 
coal  are  of  great  thickness,  but  in  many  cases  the  miner  has  to  lie 
on  his  side  and  use  the  pick  in  that  position.  Machines  do  not 
answer  well  in  thin  seams,  where,  after  the  coal  is  broken  down,  the 
men  have  to  push  it  out  of  their  rooms  with  their  feet. 


COAL  AND   COAL-MINING.  9 

The  utilization  of  coal  for  raising  steam  has  now  been  adopted 
for  many  years,  and  the  steam-engine  may  be  called  a  machine 
whereby  the  power  stored  in  the  coal  may  be  rendered  available 
for  the  performing  of  mechanical  work. 

The  history  of  the  steam-engine,  like  that  of  other  important 
inventions,  shows  a  slow  and  gradual  development  from  compara- 
tively simple  and  rude  appliances  to  the  highly  finished  and  complex 
machine  of  the  present  day. 

The  earliest  notice  which  we  have  of  the  use  of  steam  is  in  the 
writings  of  Hero  of  Alexandria  (B.C.  I20),  where  a  rotatory  steam- 
engine  is  mentioned.  In  1663  the  Marquis  of  Worcester  devised  a 
steam-engine  for  pumping  water,  and  in  1697  Savery  applied  steam 
to  pump  water  out  of  mines.  Papin  in  1690  improved  the  earlier 
rude  machine,  and  introduced  the  cylinder  and  piston.  Newcomen 
in  1705  introduced  the  separate  boiler,  and  through  the  alternate 
pressure  and  condensation  of  the  steam  produced  the  atmospheric 
pumping  engine. 

To  James  Watt,  however,  we  must  look  as  the  inventor  who 
brought  the  steam-engine  to  be  a  really  serviceable  machine  for 
commercial  purposes,  and  this  mainly  through  his  invention  of  the 
separate  condenser,  whereby  the  steam,  instead  of  being  condensed 
in  the  cylinder,  as  in  Newcomen's  engine,  was  conveyed  to  a 
separate  vessel,  where,  by  means  of  a  jet  of  water,  it  became  con- 
densed and  afterwards  pumped  out  to  be  used  as  feed-water  to  the 
boiler. 

Attempts  were  made  from  time  to  time  to  use  the  steam-engine 
as  a  propelling  power  for  boats,  and  both  in  Europe  and  in  America 
various  experiments  were  made.  To  Fulton  in  America  and  Bell 
in  this  country,  however,  the  credit  of  successfully  introducing 
passenger  steamers  must  be  given. 

The  application  of  steam  to  locomotives  was  attempted  by  vari- 
ous engineers,  but  the  successful  introduction  of  the  railway  loco- 
motive is  mainly  due  to  George  Stephenson;  the  main  elements  of 
success  being  the  adoption  of  the  tubular  boiler  and  forced  blast. 
Steam  has  also  been  applied  to  road  locomotive  traction  engines 
and  agricultural  machinery,  and,  of  course,  in  the  many  forms  of 
land  engines  it  is  still  supreme. 


BOILERS    FOR   STATIONARY    ENGINES. 


DISTINCTIVE   FORMS   OF   BOILERS. 


The  common  cylindrical  boiler  with  hemispherical  ends  is  exten- 
sively used  for  colliery  engines  and  other  places  where  space  is  no 
object,  and  the  consumption  of  fuel  but  little  thought  of.  For  such 
purposes  it  is  the  simplest,  and,  as  no  stays  are  required,  the 
strongest  of  its  kind.  It  rests  on  a  structure  of  brickwork,  having 
the  furnace  underneath,  with  a  return  flue  all  round;  the  parts  ex- 
posed to  the  action  of  the  flame  are  lined  with  fire-brick.  As  there 
are  usually  no  internal  flues,  it  is  obvious  that  it  is  a  very  safe 
boiler,  having  always  a  good  body  of  water  over  the  furnace,  or 
fire-grate;  but  still  it  is  not  free  from  the  rapid  corrosion  that  sets  in 
with  all  boilers  resting  on  a  substructure  of  brickwork.  Sometimes 
boilers  of  this  form  have  the  front  end  quite  flat,  for  the  conveni- 
ence of  attaching  the  water  gauge  glass,  steam-pressure  gauge,  &c. 


E 

A 

D 

C 

B 

=-^==^= 

^  -r: 

m 

=r- 

—      

—  ■ 

Fig.  2. — Cornish  Boiler  with  Single  Furnace.     Longitudinal  and  Transverse  Sections. 
A,  Shell.     B,  Furnace.     C,  Fire-briclc  bridge.     D,  Flue.     E,  Steam  dome. 

The  Cornish  boiler  differs  materially  from  the  plain  cylindrical  form: 
both  the  ends  are  quite  flat,  with  one  internal  flue  running  through 
and  through,  and  having  the  fire-grate  at  one  end ;  or  with  one  in- 
ternal flue,  and  having  the  furnace  underneath  the  boiler,  with  return 
flues  in  the  usual  manner.  Another  form  has  two  internal  furnaces, 
meeting  in  a  combustion  chamber.  This  plan  of  construcLion  is 
well  suited  for  the  prevention  of  smoke;  but  to  attain  this  end  the 
furnaces  should  be  fired  alternately,  so  that  one  fire  is  quite  bright, 
while  the  other  one  is  green,  or  in  the  act  of  firing.  To  assist  com- 
bustion, small  tubes  are  introduced  from  the  front  end,  passing 
through  the  water  space  into  the  combustion  chamber.     Thus  a 


BOILERS   FOR   STATIONARY   ENGINES. 


II 


current  of  heated  air  mixes  with  the  flame  and  heated  gases,  and 
prevents  smoke  to  a  great  extent.  The  simpHcity  of  this  arrange- 
ment cannot  be  excelled,  as  careful  firing  of  itself  will,  in  a  great 
measure,  prevent  smoke,  while  the  current  of  hot  air,  mixing  with 
the  heated  gases  in  the  furnace,  largely  contributes  to  the  same 
result.  The  top  parts  of  the  ends  are  stayed  with  gusset  pieces,  con- 
nected to  the  top  and  ends  of  the  boiler,  and  the  combustion  chamber 
is  strengthened  at  the  back  of  the  furnace  with  one  or  more  conical 


Fig.  3.— Boiler  with  Double  Furnaces.     Horizontal  and  Transverse  Sections. 
A,  Shell.     B  B,  Furnaces,     c,  Combustion  chamber,     d  u.  Stay  tubes,     e  e,  Flues.     F,  Steam  dome. 

tubes,  with  the  water  freely  passing  through  them.  As  large  flues 
are  weak,  sometimes  they  are  strengthened  with  conical  tubes  at 
intervals;  the  back  flue,  in  some  cases,  is  divided  into  two  smaller 
ones,  and  the  conical  tubes  omitted,  thus  leaving  the  flues  quite 
clear,  so  that  they  can  be  easily  cleaned  out.     Another  kind  of 


Fig.  4. — Combined  Cornish  and  Multitubular  Boiler.     Horizontal  and  Transverse  Sections. 
A,  Shell.     B  B,  Furnaces,     c,  Combustion  chamber.     D,  Small  tubes.     E,  Stay  tube.     F,  Steam  dome. 


cylindrical  boiler  has  a  number  of  small  tubes  set  at  the  back  of 
the  combustion  chamber,  thus  combining,  in  some  respects,  the 
Cornish  with  the  multitubular  arrangement.  For  low  pressure 
steam,  and  where  space  is  an  object,  and  when  deposits  from 
the  water  are  rapidly  formed  over  the  heating  surface,  a  self-con- 
tained boiler,  designed  by  the  author,  has  done  good  service.  It 
is  fitted  with  one  round  furnace,  carrying  the  flame  and  heated 
gases  to  the  back,  returning  to  the  front  end  through  large  tubes, 
8  inches  in  diameter,  and  then  repassing  to  the  back  through  other 


12 


MODERN    STEAM   PRACTICE. 


A,  Shell.  D  D,  Tubes. 

B,  Furnace.  E,  Smoke-box. 

C,  Combustion  chamber.   F,  Flue. 


tubes  of  the  same  diameter ;  then  down  at  the  back,  and  along  the 
sides  and   bottom,  through  suitable  flues    of  brickwork,  so  that, 

internally  and  externally,  a  large 
amount  of  heating  surface  is  ob- 
tained, and  this  great  desideratum 
is  secured  that  all  the  tubes  are 
easily  got  at  for  repairs  and  scaling 
off  the  deposits. 

Thus  we  have  noticed  arrange- 
ments partly  self-contained,  but 
having  external  flues  of  brickwork, 
such  as  are  in  general  use.  Next 
comes  that  class  which  is  wholly 
self-contained,  the  heated  gases, 
after  doing  duty  in  the  boiler,  sim- 
ply going  up  the  chimney.  There 
are  several  arrangements  having  all  the  same  object  in  view, 
namely,  to  economize  space.  By  one  of  them  an  ordinary  round 
shell  has  a  square  furnace  fitted ;  the  flame,  after  doing  its  best  duty 
in  the  fire-box,  passes  through  one  or  two  large  flues,  crossed  with 
a  series  of  conical  tube  stays,  and  the  flame  interlacing,  as  it  were, 


Fig.  s. — Return  Tubular  Boiler, 
tudinal  Section. 


E 

A 

—               l^T=V. 

8"^    8c^    8 

B              i 

^^^^  ^=-'-                -  ^=-^--^=F;r^'- 

Fig.  6. — Self-contained  Flue  Boiler.     Longitudinal  and  Transverse  Sections. 
A,  Shell.     B,  Fire-box.     c  c,  Flues,     d,  Stay  tubes,     e,  Steam  dome,     f.  Fire-door. 

amongst  them,  makes  a  very  effective  arrangement,  and  in  cases  where 
the  water,  from  its  impure  state,  rapidly  forms  deposit,  all  the  parts 
can  easily  be  reached.  Instead  of  the  large  flues,  small  tubes  are 
sometimes  arranged,  as  in  the  locomotive  boiler,  so  that  the  useful 
caloric  is  extracted  by  honeycombing  the  water,  as  it  were,  with 
hundreds  of  square  feet  of  heated  surface;  but  when  very  small  tubes 
are  used,  they  should  be  of  a  different  material  from  the  boiler — 
brass,  or  composition  tubes,  are  to  be  preferred — thus  the  incrusta- 
tion is  in  a  great  measure  prevented.  Sometimes  the  fire-box  is 
made  cylindrical,  having  a  hemispherical  outside  dome ;  by  this 


BOILERS   FOR   STATIONARY   ENGINES. 


13 


plan  very  few  stays  are  required ;  the  tube-plate,  however,  must  be 
made  flat,  with  the  back  of  the  outside  fire-box  to  correspond,  or  as  it 
were  part  of  the  cylindri- 
cal portion  of  the  fire-box, 
cut  away  in  the  plan,  that 
part  having  screwed  stays 
in  the  usual  manner.  This 
arrangement  has  now  be- 
come obsolete. 

Another  form  exten- 
sively used  for  general  purposes  is  the  vertical  type.  Such  boilers 
are  made  entirely  cylindrical ;  some  are  constructed  with  an  internal 
barrel,  with  the  smoke-pipe  passing  through  the  steam  space;  while 

A,  Shell.         c,  Smoke-pipe. 

B,  Fire-box.  D,  Fire-door. 


Fig.  7. — Self-contained  Tubular  Boiler 


A,  Shell.     B,  Fire-box.     c,  Tubes.     D,  Smoke-box. 
E,  Fire-door. 


Fig.  8. 
Vertical  Dome  Boiler. 


Fig.  9. 
Vertical  Tubular  Boiler. 


Fig.  10. 
Vertical  Return  Boiler. 


some  steam  generators  of  this  kind  are  made  very  lofty,  fitted  with 
an  internal  cone  fire-box,  and  arranged  in  communication  with  the 
waste  heat  from  puddling  and  other  furnaces,  &c.,  and  others  for 
general  purposes  have  small  tubes  placed  vertically,  arranged  with 
the  smoke-box  underneath  the  water,  and  the  smoke-pipe  passing 
through  the  steam  space.  Other  arrangements  have  the  tubes 
passing  to  the  top  of  the  boiler,  with  a  dry  uptake;  thus  the  tubes 
can  easily  be  inspected  without  disturbing  the  steam-tight  portions 
of  the  boiler;  and  the  tubes  are  easily  cleaned  by  simply  taking  off 
the  dry  uptake,  or  lower  portion  of  the  funnel.     The  boiler-tubes 


14 


MODERN    STEAM    PRACTICE, 


of  a  steam  carriage  for  common  roads  having  become  foul  with 
soot,  thus  impeding  the  draught,  gunpowder  was  wrapped  up  tightly 
in  a  piece  of  paper  and  thrown  on  the  fire,  and  the  fire-box  door 
immediately  shut;  a  slight  explosion  took  place,  sending  a  cloud  of 
soot  up  the  chimney,  effectually  clearing  the  tubes  without  stopping 
the  machine.  Of  course,  it  would  be  somewhat  dangerous  to  carry 
an  explosive  mixture  about  for  such  a  purpose;  but,  in  most  cases, 
this  means  of  clearing  the  tubes  can  be  cheaply  and  most  effectu- 
ally carried  out,  and  there  is  no  danger  whatever,  provided  too 
much  gunpowder  is  not  used  at  once.  All  vertical  self-contained 
boilers  should  have  air  tubes  ^  inch  in  diameter,  and  spaced  about 
6  inches  apart,  all  round  the  fire-box,  dipping  downwards,  so  that 
a  current  of  air  may  mix  with  the  flame  and  heated  gases  at  about 
the  level  of  the  top  of  the  fuel,  thus  tending  to  the  prevention  of 
smoke;  these  tubes  are  screwed  into  the  outside  shell  and  the 
inside  fire-box,  and  then  rivetted  over. 

There  is  one  objection  common  to  all  vertical  boilers,  namely,  that 
a  great  portion  of  the  heat  passes  directly  up  the  chimney  without 
doing  duty;  to  obviate  this  defect  the  flame  and  heated  gases  are 
directed  downwards  with  suitable  flues;  this  plan  must  have  separate 
flues  of  fire-brick,  with  a  chimney,  and  is  not  so  compact  an  arrange- 
ment as  the  multitubular  one.  The  feed-water  pipe  passes  through 
the  bottom  flues,  thus  heating  the  water  in  its  passage  to  the  boiler, 
and  all  the  flues  are  easily  reached  for  scaling  and  cleaning  out. 

The  pot  boiler  derives  its  name  from  the 
peculiar  pot-like  vessel,  fitted  to,  and  hanging 
from  the  top  of  the  fire-box;  this  spherical 
generator  is  introduced  so  that  the  lower  part, 
made  of  copper,  receives  the  full  benefit  of  the 
flame;  the  annular  space  between  the  pot  and 
the  fire-box  is  made  narrow,  thus  the  flame  and 
heated  gases  impinge  against  the  sides  of  the 
fire-box,  and  then  pass  through  the  small  tubes 
into  the  chimney.  The  ebullition  of  the  water  in 
the  pot  is  very  violent,  ejecting  the  sediment  and 
preventing  incrustation  ;  the  deposit  finds  its  way 
to  the  bottom  of  the  boiler,  and  is  cleaned  out  by 
Fig- !i-P'«  Boiler.  A  Shell,  suitable  sludge  doors.     The  dry  uptake  can  be 

B,  Fire-box.  c,  Pot.  D, Tubes.  '^  J         r 

E.Fire-door.  F,Smoke-pipe.  easily  removcd,  and  the  inside  of  the  boiler  in- 
spected through  the  man-hole,  placed  exactly  over  the  pot,  in  the 


BOILERS   FOR   STATIONARY   ENGINES. 


15 


centre  of  the  boiler,  there  being  no  tubes  at  the  centre,  but  merely 
all  round  the  opening  in  the  top  of  the  pot,  which  is  bolted  to  the 
tube-plate  by  means  of  projecting  flanges  on  the  pot  and  tube- 
plate. 

In  some  cases,  such  as  in  the  Fire-engine,  it  is  a  desideratum 
to  have  a  rapid  steam-producing  boiler;  a  good  example  is  simply 
an  ordinary  vertical  boiler,  having  the  tubes  suspended  inside  of 
the  fire-box,  arranged  with  an  internal  tube  in  each,  loosely  sup- 
ported from  the  tube-plate,  these  small  inside  tubes  leaving  annular 
spaces  between  them  and  the  larger  tubes,  so  that  only  a  thin  film 
of  water  is  exposed  to  the  heating  surface.  By  this  means  steam  is 
raised  rapidly;  but  it  must  be  borne  in  mind  that,  as  the  evapora- 
tion of  the  water  is  very  great,  care  must  be 
taken  that  a  sufficient  quantity  of  water  is  kept 
up  in  the  boiler,  which  would  otherwise  soon 
boil  dry.  The  circulation  is  very  rapid  in  the 
tubes.  The  bottoms  of  the  tubes  are  hermeti- 
cally sealed ;  and  as  the  steam  is  generated, 
it  ascends,  displacing  the  water  in  the  annular 
space  between  the  inner  and  outer  tubes,  and 
the  water  from  the  top  circulates  down  the 
inner  tubes  and  fills  up  the  cavity.  The  smoke- 
pipe  is  connected  to  the  top  of  the  fire-box, 
passing  through  the  steam  space,  and  is  rivetted 
to  an  angle-iron  ring  on  the  top  of  the  boiler; 
and  there  is  an  open  part  left  in  the  centre  of 
the  fire-box  where  there  are  no  tubes,  this 
opening  being  blocked  up  with  a  lump  of  fire- 
brick suspended  by  a  rod  from  the  top  of  the 
boiler,  thus  the  flame  is  prevented  from  going  directly  up  the 
chimney,  as  it  impinges  against  the  fire-clay  lump,  and  by  this 
means  it  is  distributed  beneficially  amongst  the  small  tubes. 

Instead  of  a  number  of  annular  tubes,  one  large  tube  has  been  suc- 
cessfully adopted,  the  arrangement  consisting  of  an  internal  fire-box, 
having  an  annular^  water  space  all  round.  On  the  outside  of  this 
water  space  there  is  an  annular  flue,  and  the  whole  is  contained  in 
an  ordinary  vertical  boiler,  having  a  hemispherical  top ;  the  flame 
and  the   gases,    after  doing  duty  in  the  fire-box,  find  their  way 


Fig.  12. — Boiler  with  Suspended 
Annular  Tubes.  A,  Shell. 
B,  Fire-bo.x.  c,  Tubes.  D,  Fire- 
brick lump.  E,  Smoke-pipe. 
F,  Fire-door 


*  The  space  between  a  small  inner  and  large  outer  tube  is  called  annular. 


i6 


MODERN   STEAM   PRACTICE. 


Fig.  13. — Annular  Boiler.  A,  Shell.  B,  Fire- 
box, c,  Annular  water  space.  D,  Annular 
flue.    E,  Flue,     f,  Fire-door,    g,  Ash-pit. 


through  an  opening  into  the  annular  flue,  and  then  escape  all  round 
into  a  flue  of  brickwork;   thus  a  large  heating  surface  is  obtained. 

As  in  the  pot  boiler,  there  is  great 
ebullition  in  the  annular  space  around 
the  inside  fire-box,  the  steam  escaping 
into  the  boiler  proper  through  a  tube 
at  the  top,  the  circulation  of  the  water 
being  effected  by  a  series  of  small 
tubes,  connecting  the  inside  and  the 
outside  water  spaces  at  the  bottom  of 
the  boiler. 

What  are  termed  "water-tube" 
boilers  show  examples  consisting 
merely  of  large  tubes,  so  connected 
as  to  form  a  series  of  boilers,  the  whole 
being  encased  in  brickwork.  This 
species  of  steam  generator  is  capable 
of  sustaining  great  pressure,  the  whole 
of  the  steam  pipes  and  the  connections  being  tested  to  about  500  lbs. 
per  square  inch;  and  as  they  are  constructed  so  that  all  the  joints 
are  protected  from  the  action  of  the  flame,  they  ought  to  be  very 
durable.  Where  space  is  no  object  they  are  well  suited  for  small 
powers,  but  for  large  power  it  is  doubtful  if  they  are  so  well  adapted 
as  the  ordinary  Cornish  arrangements,  fitted  with  conical  water 
tubes  in  the  flues. 

One  arrangement  of  the  water-tube  boiler  consists  of  a  series  of 
tubes  4  feet  6  inches  long  and  7  inches  in  diameter,  closed  at  the  upper 
ends,  having  plates  )^  inch  in  thickness  welded  in,  and  round 
the  bottom  ends  heavy  cast-iron  rings  with  lugs  are  fixed.  The 
ends  of  the  tubes  are  roughened,  and  the  rings  are  cast  on,  thus  the 
contraction  of  the  cast-iron,  as  well  as  a  partial  uniting  of  the  two 
metals,  render  this  mode  of  fastening  on  the  rings  a  very  secure  one; 
the  tubes  are  arranged  in  transverse  rows  in  an  oven,  between  the 
furnace  and  the  chimney.  The  lower  ends  of  the  tubes  for  each  row 
are  united  to  a  pipe  10  inches  in  diameter,  and  of  suitable  thickness, 
which  is  strengthened  by  diaphragm  plates  cast  in,  and  perforated 
with  small  holes.  On  this  pipe  short  branch  pieces  are  cast,  which 
are  turned  and  recessed,  for  the  reception  of  the  ends  of  the  other 
tubes,  to  which  they  are  strongly  united  by  means  of  bolts  and  gun- 
metal  nuts,  recessed  into  the  lugs,  the  rings  on  the  tubes  having 


BOILERS   FOR   STATIONARY   ENGINES. 


17 


corresponding  lugs.  The  joint  is  made  with  a  composition  ring,  of 
lead  and  tin,  dropped  into  the  recess,  and  then  the  screws  are 
tightened;  this  joint  is  capable  of  sustaining  as  great  a  pressure  as 
the  tubes,  and  can  be  made  and  re-made  at  any  time  without  injury. 


Tig.  14. — Water-tube  Boiler,     a,  Furnace,     b.  Tubes,     c,  Flue,     d.  Division  plate,     e,  Damper. 
F,  Steam  receiver.     G,  Stop  valve.     H,  Safety  valve. 

The  upper  ends  of  the  tubes  have  short  pieces  of  wrought-iron 
welded  gas  pipe,  tapped  into  the  end  plates,  for  taking  away  the 
steam  to  the  main  pipe,  which  is  placed  horizontally.  Upon  tl.e 
main  steam  pipe  smaller  pipes  are  fitted,  and  connected  to  the  small 
gas  pipes  from  each  generator;  thus  the  steam  flows  along  them  into 
the  large  pipe,  to  which  is  fixed  the  safety-valve  and  the  pipe  to 
the  steam  cylinder.  All  the  parts  are  so  arranged  that  they  can 
expand  freely,  without  disturbing  the  joints.  The  oven  has  a 
division  plate  strongly  ribbed;  by  this  means  the  flame  impinges 
on  the  bottom  halves  of  the  generators,  and  passing  along  the  top 
half  goes  to  the  chimney. 

Another  arrangement  of  water -tube  generators  has  simply 
wrought-iron  tubes,  with  cast-iron  ends,  secured  with  long  bolts 
inside  of  the  tubes,  having  the  feed  pipes  joining  together  at  the 
bottom ;  similar  pipes  are  situated  at  the  top  of  the  tubes  for  the 
steam,  these  lead  into  one  main  steam  pipe,  the  whole  being 
encased  in  suitable  brickwork.  All  the  parts  in  this  arrangement 
are  well  protected,  only  the  plain  parts  of  the  tubes  being  exposed 

2 


iS 


MODERN   STEAM   PRACTICE. 


to  the  action  of  the  flame;  the  bottom  joints  are  embedded  in 
the  brickwork,  and  each  of  the  tubes  exposes  an  area  of  i6  feet, 


A,  Shell.  B,  Fire-box.  c,  Smoke- 
pipe.  D,  Circulating  water 
space.  E,  Conical  tubes.  F,  Fire- 
door.  G,  Sludge  cap 


Fig.  IS. — Water-tube  Boiler.     A,  Furnace.     B,  Tubes.     C,  Flue. 
D  D,  Division  plates.    E,  Damper,    f,  Stop  valve.    G,  Chimney. 


Fig.  16. — Self-contained  Water- 
tube  Boiler. 


equal  to  one  horse-powc-.  This  arrange- 
ment is  certainly  very  simple,  and  is  to 
be  commended,  provided  the  expansion 
of  the  long  bolts  does  not  affect  the  caps 
at  the  ends,  causing  steam  to  blow  at  the 
joints.  These  water-tube  boilers  must  be 
so  manufactured  that  no  destructive  ex- 
pansion may  be  allowed  to  take  place,  and  all  the  joints  should  be 
metal  to  metal  where  practicable. 

Water-tube  boilers,  sometimes  called  tubulous,  may  be  of  various 
forms.  The  water  tubes  can  be  arranged  in  a  variety  of  ways, 
so  that  the  furnaces,  the  tubes,  and  the  shell  are  self-contained. 
Thus  to  an  ordinary  vertical  boiler  an  inside  fire-box  is  fitted,  as 
likewise  a  pot-shaped  vessel  connected  by  circulating  pipes  with  the 
shell,  as  shown  by  Figs.  15  and  16.  A  current  of  water  is  continually 
descending  between  the  fire-box  and  the  outside  shell,  and  finds  its 
way  into  the  pot  through  the  circulating  pipes  at  the  bottom.  These 
boilers  keep  free  from  deposit,  owing  to  the  rapid  circulation,  and 
for  some  purposes  are  recommended  to  be  arranged  with  conical  or 
common  tubes. 


BOILERS   FOR   STATIONARY   ENGINES.  I9 

In  the  Perkins  system  of  boiler  a  large  number  of  water  tubes  are 
enclosed  in  a  double  shell  of  plate  iron,  the  space  being  filled  with  a 
non-conducting  medium.  The  tubes  are  2^  inches  inside  diameter 
and  ^  inch  thick.  About  one  half  of  the  tubes  are  used  for  generat- 
ing steam,  the  other  half  being  used  for  superheating.  The  boiler  is 
supplied  with  distilled  water,  and  the  furnace  is  placed  beneath  the 
tubes  which  run  vertically  above.  Tubulous  boilers  have  been  tried 
at  sea  in  the  Propontis  and  other  vessels  on  Rowan's  system,  and 
again  recently  in  the  steam  yacht  Anthracite,  which  lately  made 
a  voyage  across  the  Atlantic  and  back,  carrying  a  pressure  of  from 
300  to  500  lbs.  of  steam  per  square  inch.  This  vessel  was  fitted 
with  the  Perkins  boiler. 

ON   BOILERS,    BY   FAIRBAIRN. 

We  propose  under  this  head  to  consider  the  steam-boiler  in  its 
construction,  management,  security,  and  economy. 

As  regards  the  construction,  it  is  absolutely  necessary  to  study 
carefully  the  shapes  which  give  maximum  strength,  and  require 
minimum  of  material.  In  boilers  this  is  most  important,  as  any 
increase  in  the  thickness  of  the  plate  obstructs  the  transmission 
of  heat,  and  exposes  them  as  well  as  the  rivets  to  injury  on  the  side 
exposed  to  the  action  of  the  flame.  It  has  been  generally  supposed 
that  the  rolling  of  boiler  plates  gives  to  the  sheets  greater  tenacity 
in  the  direction  of  their  length  than  in  that  of  their  breadth.  This  is, 
however,  not  always  the  case,  as  experiments  show  that  the  tensile 
strain  across  the  fibre  of  boiler  plates  is  in  some  samples  greater  than 
their  tensile  strength  when  torn  asunder  in  the  direction  of  the  fibre. 
We  consider  this  may  be  owing  to  the  way  the  iron  is  piled  before 
putting  it  through  the  rolls;  more  recent  experiments  plainly  show 
that  the  tensile  strength  of  boiler  plates  is  slightly  greater  in  the 
direction  of  the  fibre,  and  from  this  it  would  appear  that  although 
it  is  more  convenient  to  construct  circular  boilers,  with  plates  rolled 
in  the  direction  of  the  fibre,  still  we  think  that  boilers  diagonally 
plated  are  the  strongest. 

Next  to  the  tenacity  of  the  plates  comes  the  question  of  rivet- 
ting.  On  this  point  we  have  been  widely  astray,  and  it  required 
some  skill,  and  no  inconsiderable  attention  in  conducting  the  ex- 
periments, to  convince  even  some  practical  men  that  the  rivetted 
joints  were  not  stronger  than  the  plate  itself  In  punching  holes 
along  the  edge  of  a  plate,  it  is  obvious  that  the  plates  must  be 


20  MODERN    STEAM   PRACTICE. 

weakened  to  the  extent  of  the  sectional  area  punched  out;  and 
it  is  found  also  that  the  metal  between  the  holes  is  deteriorated 
by  the  process  of  punching.^  This  deteriorating  result  was  clearly 
demonstrated  by  a  series  of  experiments  which  took  place  some 
years  ago,  and  in  which  the  strength  of  almost  every  descrip- 
tion of  rivetted  joints  was  determined  by  tearing  each  directly 
asunder.  The  results  obtained  from  these  experiments  were  con- 
clusive as  regards  the  relative  strength  of  rivetted  joints  and  the 
solid  plates.  In  two  different  kinds  of  joints,  double  and  single 
rivetted,  the  strength  was  found  to  be  in  the  ratio  of  lOO  for  the  solid 
plate,  70  was  the  strength  of  a  double-rivetted  joint  after  allowing 
for  the  adhesion  of  the  surfaces  of  the  plates,  and  56  was  the  strength 
of  a  single-rivetted  joint.  These  proportions  of  relative  strength  of 
plates  and  joints  may  therefore  in  practice  be  safely  taken  as  the 
standard  value  in  the  construction  of  vessels  required  to  be  steam 
and  water  tight,  and  subjected  to  pressure  varying  from  10  lbs.  to 
100  lbs.  on  the  square  inch. 

The  following  is  the  rule  for  proportions  as  given  by  Professor 
Rankine:^ — 

"  Let  r  denote  the  radius  of  a  thin  hollow  cylinder,  such  as  the 
shell  of  a  high-pressure  boiler;  /,  the  thickness  of  the  shell;  /  the 
tenacity  of  the  material  in  lbs.  per  square  inch;  /,  the  intensity 
of  the  pressure  in  lbs.  per  square  inch  required  to  burst  the  shell. 
This  ought  to  be  taken  at  SIX  TIMES  the  effective  working  pressure, 
then  /  =  ^ ,  and  the  proper  proportion  of  thickness  to  radius  is  given 

by  the  formula  y  ■=■  j." 

"The  following  formula  gives  approximately  the  collapsing  pressure 
p  in  lbs.  on  the  square  inch  of  a  plate  iron  flue,  whose  length  /, 
diameter  d,  and  thickness  t,  are  all  expressed  in  the  same  units  of 

measure:  p  —  9,672,000  ^." 

"Tenacity  of  wrought-iron  plates  =  51,000  lbs.  per  square  inch. 
Tenacity  of  wrought-iron  joints,  double  rivetted  =  35,700  lbs.  per  square  inch. 
Tenacity  of  wrought-iron  joints,  single  rivetted  =  28,600  lbs.  per  square  inch." 

In  the  construction  of  boilers  exposed  to  severe  internal  pressure, 
it  is  desirable  to  adopt  such  forms,  and  so  to  dispose  the  material, 
as  to  apply  the  greatest  strength  in  the  direction  of  the  greatest 

*  In  the  best  modern  practice,  therefore,  all  rivet  holes  are  drilled  where  practicable. 
»  See  Manual  of  the  Steam  Engine. 


BOILERS   FOR   STATIONARY   ENGINES.  21 

strain.  Professor  W.  R.  Johnson,  of  the  Frankhn  Institute  of 
America,  whose  inquiries  into  the  strength  of  cyhndrical  boilers 
are  of  great  value,  may  be  quoted  as  an  authority: — 

"  1st.  To  know  the  force  which  tends  to  burst  a  cylindrical  boiler 
in  the  longitudinal  direction,  or,  in  other  words,  to  separate  the  head 
from  the  curved  sides,  we  have  only  to  consider  the  actual  area  of 
the  head,  and  to  multiply  the  units  of  surface  by  the  number  of 
units  oi  force,  applied  to  each  superficial  unit,  this  will  give  the  total 
divellent.  To  counteract  this,  we  have,  or  may  be  conceived  to  have, 
the  tenacity  of  as  many  longitudinal  bars  as  there  are  units  in  the 
circumference  of  the  cylinder.  The  united  strength  of  these  bars 
constitutes  the  total  retaining  or  quiescent  force,  and  at  the  moment 
when  rupture  is  about  to  take  place  the  divellent  and  quiescent 
forces  must  obviously  be  equal. 

"  2d.  To  ascertain  the  amount  of  force  which  tends  to  rupture  the 
cylinder  along  the  curved  side,  or  rather  along  the  opposite  sides,  we 
may  consider  the  pressure  as  applied  through  the  whole  breadth  of  the 
cylinder  upon  each  lineal  unit  of  diameter.  Hence  the  total  amount 
of  force  which  would  tend  to  divide  the  cylinder  in  halves,  by  sepa- 
rating it  along  two  lines  of  opposite  sides,  would  be  represented  by 
multiplying  the  diameter  by  the  force  exerted  on  each  unit  of  surface, 
and  this  product  by  the  length  of  the  cylinder.  But  even  without 
regarding  the  length,  we  may  consider  the  force  requisite  to  rupture 
a  single  band  in  the  direction  now  supposed,  and  of  one  lineal  foot 
in  breadtJi,  since  it  obviously  makes  no  difference  whether  the  cylinder 
be  long  or  short,  in  respect  to  the  ease  or  difficulty  of  separating  the 
sides.  When  the  diameter  of  a  boiler  is  increased,  it  must  be  borne 
in  mind  that  the  area  of  the  ends  is  also  increased,  not  in  the  ratio 
of  the  diameter,  but  in  the  ratio  of  the  square  of  the  diameter;  and 
it  will  be  seen,  that  instead  of  the  force  being  doubled,  as  in  the  case 
of  the  direction  of  the  diameter  and  circumference,  it  is  quadrupled 
upon  the  ends,  or,  what  is  the  same  thing,  a  cylinder  double  the 
diameter  of  another  cylinder,  has  four  times  the  pressure  in  the 
longitudinal  direction.  The  retaining  force,  or  the  thickness  of  metal 
of  a  cylindrical  boiler,  does  not,  however,  increase  in  the  same  ratio 
as  the  area  of  the  circle,  but  simply  in  the  ratio  of  the  diameter, 
consequently  the  thickness  of  the  metal  will  require  to  be  increased 
in  the  same  ratio  as  the  diameter  is  increased.  From  this  it  appears 
that  the  tendency  to  rupture,  by  blowing  out  the  ends  of  a  cylindri- 
cal boiler,  will  not  be  greater  in  this  direction  than  it  is  in  any  other 


22  MODERN    STEAM   PRACTICE. 

direction;  we  may  therefore  safely  conclude,  since  we  have  seen 
that  the  tendency  to  rupture  increases  in  both  directions  in  the 
ratio  of  the  diameter,  that  any  deviation  from  that  law,  as  regards 
the  thickness  of  the  plates,  would  not  increase  the  strength  of  the 
boiler." 

We  have  been  led  to  the  following  inquiries  from  the  circumstance 
that  Mr.  Johnson  appears  to  reason  on  the  supposition  that  there 
are  no  joints  in  the  plates,  and  that  the  tenacity  of  the  iron  is  equal 
to  60,000  lbs.,  rather  more  than  26  tons,  to  the  square  inch.  Now  the 
result  of  experiment  has  shown  that  ordinary  boiler  plates  will  not 
bear  more  than  23  tons  to  the  square  inch;  and  as  nearly  one- third 
of  the  material  is  punched  out  for  the  reception  of  the  rivets,  we  must 
still  further  reduce  the  strength,  and  take  1 5  tons,  or  about  34,000  lbs., 
on  the  square  inch,  as  the  tenacity  of  the  boiler  plates,  or  the  pres- 
sure at  which  the  boiler  would  burst.  By  experiment  it  has  been 
found  that  the  strength  of  the  single-rivetted  joints  of  boilers  is  little 
more  than  half  the  strength  of  the  plate  itself;  but  taking  into 
consideration  the  crossing  of  the  joints,  34,000  lbs.  may  reasonably 
be  taken  as  the  tenacity  of  the  rivetted  plates,  or  the  bursting 
pressure  of  a  cylindrical  boiler. 

It  has  been  stated  that  the  strength  of  cylindrical  boilers,  when 
taken  in  the  direction  of  their  circumference,  is  in  the  ratio  of  their 
diameters,  and  when  taken  in  the  direction  of  the  ends,  as  the  squares 
of  the  diameters;  a  proposition  which  it  will  be  difficult  to  demonstrate 
as  applicable  to  every  description  of  boiler  of  the  cylindrical  form. 
It  will  be  seen,  however,  that  the- strain  is  not  exactly  the  same  in 
every  direction,  and  that  there  is  actually  less  upon  the  material  in 
the  longitudinal  direction  than  there  is  upon  the  circumference.  For 
example,  let  us  take  two  boilers,  one  3  feet  in  diameter  and  the  other 
6  feet  in  diameter,  and  suppose  each  to  be  subjected  to  a  pressure 
of  40  lbs.  to  the  square  inch.  In  this  condition,  it  is  evident  that 
the  area,  or  number  of  square  inches,  in  the  end  of  the  3  feet  boiler 
is  to  that  of  the  area  of  the  6  feet  boiler  as  i  to  4 ;  and,  by  a  common 
process  of  arithmetic,  it  is  found  that  the  edges  of  the  plates  forming 
the  cylindrical  part  of  the  3  feet  boiler  is  subject,  at  40  lbs.  on  the 
square  inch,  to  a  pressure  of  40,714  lbs.,  or  upwards  of  18  tons; 
whereas  the  plates  of  a  6  feet  boiler  have  to  sustain  a  pressure  of 
162,856  lbs.,  or  72  tons,  which  is  quadruple  the  force  to  which  the 
boiler  only  one-half  of  the  diameter  is  exposed;  and  the  circumfer- 
ence being  only  as  2  to  i,  there  is  necessarily  double  the  strain  upon 


BOILERS   FOR   STATIONARY   ENGINES.  23 

the  cylindrical  plates  of  the  large  boiler.  Now  this  is  not  the  case 
with  the  other  parts  of  the  boiler,  as  the  circumference  of  a  cylinder 
increases  only  in  the  ratio  of  the  diameter,  consequently  the  pressure 
instead  of  being  increased  in  the  ratio  of  the  squares  of  the  diameter, 
as  shown  in  the  ends,  is  only  doubled,  the  circumference  of  the 
6  feet  boiler  being  twice  that  of  the  3  feet  boiler. 

Let  us,  for  the  sake  of  illustration,  suppose  the  two  cylindrical 
boilers  such  as  we  have  described  to  be  divided  into  a  series  of  hoops 
of  I  inch  width,  and  taking  one  of  these  hoops  in  the  3  feet  boiler,  we 
shall  find  it  exposed  at  a  pressure  of  40  lbs.  on  the  square  inch  to  a 
force  of  1440  acting  on  each  side  of  a  line  drawn  through  the  axis  of 
a  cylinder  36  inches  diameter  and  i  inch  in  depth,  and  which  line  forms 
the  diameter  of  the  circle.  Now  this  force  causes  a  strain  tending  to 
burst  the  hoops  in  the  3  feet  circle  of  720  lbs.,  and  assuming  the  pres- 
sure to  be  increased  until  the  force  becomes  equal  to  the  tenacity  or 
retaining  power  of  the  material,  it  is  evident,  in  this  state  of  the  equi- 
librium of  the  two  forces,  that  the  preponderance  on  the  side  of  the 
internal  pressure  would  insure  fracture;  and  supposing  we  take  the 
plates  of  which  the  boiler  is  composed,  of  one  quarter  of  an  inch  thick, 
and  the  ultimate  strength  at  34,000  lbs.  on  the  square  inch,  we  shall 
have  ^^°°°  =  472  lbs.  per  square  inch,  as  the  bursting  pressure  of  the 
boiler.  Again,  as  the  forces  in  this  direction  are  not  as  the  squares, 
but  simply  as  the  diameters,  it  is  clear  that  at  40  lbs.  on  the  square 
inch  we  have  in  a  hoop  an  inch  in  depth,  or  that  portion  of  a  cylinder 
whose  diameter  is  6  feet,  exactly  double  the  force  applied  to  rend 
the  iron  asunder,  as  in  the  3  feet  boiler.  Now,  assuming  the  plates 
to  be  quarter  of  an  inch  thick,  as  in  the  3  feet  boiler,  it  follows,  if 
the  forces  at  the  same  pressure  be  doubled  in  the  large  cylinder,  that 
the  thickness  of  the  plates  must  also  be  doubled,  in  order  to  sustain 
the  same  pressure  with  equal  security;  or,  what  is  the  same  thing, 
the  6  feet  boiler  must  be  worked  at  half  the  pressure,  in  order  to 
secure  the  same  degree  of  safety  as  attained  in  the  3  feet  boiler  at  the 
given  pressure.  From  these  facts  it  may  be  useful  to  know  that 
boilers  having  increased  dimensions,  should  also  have  increased 
strength  in  the  ratio  of  their  diameters;  or,  in  other  words,  the  plates 
of  a  6  feet  boiler  should  be  double  the  thickness  of  the  plates  of  a 
3  feet  boiler,  and  so  on  as  the  diameter  increases. 

The  relative  powers  of  force  applied  to  cylinders  of  different  dia- 
meters become  more  strikingly  apparent  when  we  reduce  them  to 
their  equivalents  of  strain  per  square  inch,  as  applied  to  the  ends 


24  MODERN   STEAM   PRACTICE. 

and  circumference  of  the  boiler  respectively.  In  the  3  feet  boiler, 
working  at  40  lbs.  pressure,  we  have  a  force  equal  to  720  lbs.  upon  an 
inch  width  of  plates,  and  one  quarter  of  an  inch  thick,  or  720  x  4  ^ 
2880  lbs.,  the  force  per  square  inch  upon  every  point  of  the  circum- 
ference of  the  boiler.  Let  us  now  compare  this  with  the  actual 
strength  of  the  rivetted  plates  themselves,  which,  taken  as  before  at 
34,000  lbs.  on  the  square  inch,  gives  the  ratio  of  the  pressure  as 
applied  to  the  strength  of  the  circumference  as  2880  to  34,000, 
nearly  as  i  to  12,  or  472  lbs.  per  square  inch  as  the  ultimate  strength 
of  the  rivetted  plates. 

These  deductions  appear  to  be  true  in  every  case  as  regards  the 
resisting  powers  of  cylindrical  boilers  to  a  force  radiating  in  every 
direction  from  its  axis  towards  the  circumference;  but  the  same 
reasoning  is,  however,  not  maintained  when  applied  to  the  ends,  or, 
to  speak  technically,  to  the  angle-iron,  and  rivetting,  when  the  ends 
are  attached  to  the  circumference.  Now,  to  prove  this,  let  us  take 
the  3  feet  boiler,  where  we  have  1 1 3  inches  in  the  circumference, 
and  upon  this  circular  line  of  connection  we  have,  at  40  lbs.  to  the 
square  inch,  to  sustain  a  pressure  of  18  tons,  which  is  equal  to  a 
strain  of  360  lbs.  acting  longitudinally  upon  every  inch  of  the  cir- 
cumference. Apply  the  same  force  to  the  6  feet  boiler,  with  a. 
circumference  or  line  of  connection  equal  to  226  inches,  and  we 
shall  find  it  exposed  to  exactly  four  times  the  force,  or  72  tons; 
but  in  this  case  it  must  be  borne  in  mind  that  the  circumference  i^^ 
doubled,  and  consequently  the  strain,  instead  of  being  quadrupled, 
is  only  doubled  on  a  force  equal  to  720  lbs.,  acting  longitudinally 
as  before  upon  every  square  inch  of  the  circumference  of  the  boiler. 
From  these  facts  we  come  to  the  conclusion  that  the  strength  of 
cylindrical  boilers  is  in  the  ratio  of  their  diameters,  if  taken  in  the 
line  of  curvature,  and  as  the  squares  of  the  diameters  as  applied 
to  the  ends  or  their  sectional  area;  and  that  all  descriptions  of 
cylindrical  tubes,  to  bear  the  same  pressure,  must  be  increased  in. 
strength  in  the  direction  of  their  circumferences,  simply  as  their 
diameters,  and  in  the  direction  of  the  ends  as  the  squares  of  the 
diameters. 

Again,  if  we  refer  to  the  comparative  merits  of  the  plates  com- 
posing cylindrical  vessels,  subjected  to  internal  pressure,  they  will 
be  found  in  the  anomalous  condition,  that  the  strength  in  their 
longitudinal  direction  is  twice  that  of  the  plates  in  the  curvilinear 
direction.     This  appears  by  a  comparison  of  the  two  forces,  wherein 


BOILERS   FOR   STATIONARY   ENGINES. 


25 


we  have  shown  that  the  ends  of  the  3  feet  boiler,  at  40  lbs,  internal 
pressure,  sustain  360  lbs.  of  longitudinal  strain  upon  each  inch  of  a 
plate  a  quarter  of  an  inch  thick;  whereas  the  same  thickness  of  plates 
have  to  bear,  in  the  curvilinear  direction,  a  strain  of  720  lbs.  This 
difference  of  strain  is  a  difficulty  not  easily  overcome ;  and  all  that 
we  can  accomplish  in  this  case  will  be  to  exercise  a  sound  judgment 
in  crossing  the  joints,  in  the  quality  of  the  workmanship,  and  in  the 
distribution  of  the  material.  For  the  attainment  of  these  objects, 
the  following  table,  which  exhibits  the  proportionate  strength  of 
cylindrical  boilers  from  3  to  8  feet,  may  be  useful : — 


Diameters  of 
Boilers. 

Bursting  Pressure  equivalent  to  the  ultimate  strength 

Thickness  of  the 

of  the  Rivetted  Joints,  as  deduced  from  experiment. 

Plates  in  decimal 

34,000  lbs.  to  the  square  inch. 

parts  of  an  inch. 

Feet.   Inches. 

3        0 

•250 

3        6 

•291 

4       0 

•333 

4        6 

•376 

5       0 
5       6 

450  lbs. 

•416 
•458 

6        0 

•500 

6        6 

•541 

7        0 

•583 

7        6 

•625 

8        0 

•666 

Boilers  of  the  simple  form,  and  without  internal  flues,  are  subjected 
only  to  one  species  of  strain ;  but  those  constructed  with  internal 
flues  are  exposed  to  the  same  tensile  force  which  pervades  the 
simple  form ;  and  farther,  to  the  force  of  compression,  which  tends 
to  collapse  or  crush  the  material  of  the  internal  flues. 

From  the  existing  state  of  our  knowledge  we  must  rest  satisfied 
that  the  flues  of  ordinary  boilers  can  be  materially  strengthened  by 
the  introduction  of  iron  hoops,  but  we  are  of  opinion  they  should 
never  be  introduced  where  deposits  rapidly  form,  such  as  in  marine 
boilers,  &c. ;  for  it  must  be  borne  in  mind  that  there  are  two  thick- 
nesses of  material  at  the  parts  hooped,  and  the  incrustation  that 
forms  proves  highly  detrimental  to  the  furnaces.  In  many  cases 
where  deposits  have  formed  at  the  hoops  the  furnace-plates  have 
bulged  out  very  much. 

Fairbairn  gives  a  table  of  internal  flues  fitted  with  T-iron  or  angle- 
iron  hoops.  The  length  of  the  flues  must  be  measured  between  the 
rigid  supports;  in  an  unsupported  flue,  as  ordinarily  constructed, 


26 


MODERN   STEAM   PRACTICE. 


the  length  is  measured  between  the  end  plates  of  the  boiler.  In 
the  flues  as  proposed,  between  the  T-iron  ribs,  the  dimensions  given 
are  for  a  collapsing  pressure  of  450  lbs.  per  square  inch;  the  safe 
working  pressure  should  be  75  lbs.  per  square  inch. 


Thickness  of  Plates.                         | 

Diameter  of 
Flues  in  inches. 

10  Feet  Long. 

20  Feet  Long. 

30  Feet  Long. 

12 

•291 

•399 

•480 

18 

■350 

•480 

•578 

24 

•399 

•548 

•659 

30 

450  lbs. 

•442 

•607 

•730 

36 

•480 

■659 

•794 

42 

•516 

•707 

•851 

48 

•548 

•752 

•905 

The  above  are  founded  on  the  supposition  that  the  20-feet  and 
30-feet  long  flues  have  T-iron  or  angle-iron  hoops  at  the  necessary 

joints,  the  hoops  to  be  placed  10  feet 
apart.    Some  makers  prefer  placing  the 
T-iron  hoops  at  each  joint,  the  plates 
Fig.  x7.-Roiied  Hoop.  butting    on   one    another,    and    at   the 

longitudinal  joints  likewise.^  When  the  joints  are  planed,  and 
the  butt  strips  properly  fitted,  the  strain  is  entirely  taken  off"  the 
rivets,  the  compressive  strain  being  taken  on  the  ends  of  the  plates 
directly. 

In  the  cylindrical  boiler,  with  round  flues,  the  forces  are  diverging 
from  the  central  axis  as  regards  the  outer  shell,  and  converging 
as  applied  to  every  separate  flue  which  the  boiler  contains.  To 
show  the  amount  of  strain  upon  a.  high  -  pressure  boiler  30  feet 
long  and  6  feet  in  diameter,  having  two  centre  flues,  each  2  feet 
3  inches  diameter,  working  at  a  pressure  of  50  lbs.  on  the  square 
inch,  we  have  only  to  multiply  the  number  of  square  feet  of  sur- 
face— 1030  exposed  to  pressure — by  3'2i,  and  we  have  the  force 
of  3306  tons  which  a  boiler  of  these  dimensions  has  to  sustain.  We 
mention  this  to  show  that  the  statistics  of  pressure,  when  worked 
out,  are  not  only  curious  in  themselves,  but  instructive  as  regards  a 
knowledge  of  the  retaining  powers  of  vessels  so  extensively  used. 


^  These  T-hoops  are  now  almost  superseded  by  rings  shaped  as  above  (Fig.  17),  and 
rolled  specially  for  the  purpose.  The  latter  answer  admirably,  and  also  allow  of  ex- 
pansion and  contraction. 


BOILERS   FOR   STATIONARY   ENGINES.  2/ 

To  pursue  the  subject  a  little  further,  let  us  suppose  the  pressure  to 
be  450  lbs.  on  the  square  inch,  which  a  well-constructed  boiler  of  this 
description  will  bear  before  it  bursts,  and  we  have  the  enormous  force 
of  29,754  tons,  or  nearly  30,000  tons,  compressed  within  a  cylinder 
30  feet  long  and  6  feet  diameter.  This  is,  however,  inconsiderable 
when  compared  with  the  locomotive  and  some  marine  boilers,  which, 
from  the  number  of  tubes  they  contain,  present  a  much  larger  surface 
to  pressure.  Locomotive  boiler  engines  are  usually  worked  at 
120  lbs.  on  the  square  inch ;  and  taking  one  of  the  usual  construction 
we  shall  find  that  it  rushes  forward  on  the  rail  with  a  pent-up 
force  within  its  interior  of  nearly  60,000  tons,  which  is  rather 
increased  than  diminished  at  an  accelerated  speed.  In  a  station- 
ary boiler,  charged  with  steam  at  a  given  pressure,  it  is  evident 
that  the  forces  are  in  equilibrium,  and  the  strain  being  the  same 
in  all  directions,  there  will  be  no  tendency  to  motion.  Supposing, 
however,  this  equilibrium  to  be  destroyed,  by  accumulative  pressure, 
till  rupture  ensues,  it  follows  that  the  forces  in  one  direction 
having  ceased,  the  others  in  an  opposite  direction,  being  active, 
would  project  the  boiler  from  its  seat  with  a  force  equal  to  that 
which  is  discharged  through  the  orifice  of  rupture.  The  direction 
of  motion  would  depend  upon  the  position  of  the  ruptured  part:  if 
in  the  line  of  the  centre  of  gravity,  motion  would  ensue  in  that  direc- 
tion; if  out  of  that  line,  an  oblique  or  rotatory  motion  round  the 
centre  of  gravity  would  be  the  result.  {An  explosion  of  a  plain 
vertical  boiler  may  be  taken  as  an  example :  it  gave  way  at  the 
bottom  of  the  fire-box  or  bottom  of  the  boiler,  and  by  the  reactive  force 
of  the  steam  it  was  lifted  about  100  feet  in  the  air  like  a  sky-rocket, 
and  when  the  force  was  spent,  and  the  water  and  the  steam  expelled, 
it  descended,  landing  on  the  identical  spot  where  it  had  rested  pre- 
vious to  the  explosion.)  The  momentum  or  quantity  of  motion  pro- 
duced in  one  direction  would  be  equal  to  the  intensity  or  quantity 
lost ;  and  the  velocity  with  which  the  body  would  move  would  be 
in  the  ratio  of  the  impulsive  force,  or  the  quantity  lost.  Therefore, 
the  quantity  of  motion  gained  by  an  exploded  boiler  in  one  direction 
will  be  as  the  weight  and  quantity  lost  in  that  direction.  These 
definitions,  however,  belong  more  to  the  province  of  the  mathemati- 
cian, and  may  be  easily  computed  from  well-known  formulae  on  the 
laws  of  motion. 

The  following  table  shows  the  bursting  pressure  of  boilers,  as 
likewise  the  safe  working  pressure,  as  deduced  from  experiment, 


28 


MODERN   STEAM   PRACTICE. 


with  a  strain  of  34,000  lbs.  on  the  square  inch  as  the  ultimate  strength 
of  ri vetted  joints: — 


XJismetGr  oi 

Working 

Bursting 

Working 

Bursting 

Pressure  for 

Pressure  for 

Pressure  for 

Pressure  for 

Boiler. 

^-inch  Plates. 

^-inch  Plates. 

J^-inch  Plates. 

J^-inch  Plates. 

ft.     in. 

3    0 

118 

708^ 

I57X 

944X 

3     3 

109 

653^ 

I45X 

8713/ 

3    6 

lOI 

607 

I34M 

8095^ 

3    9 

94^ 

566X 

125^ 

755^5^ 

4    0 

98K 

531 

118 

708X 

4     3 

83X 

500 

III 

666;5 

4    6 

78j^ 

472 

104I4: 

629'^ 

4    9 

74K 

447>^ 

99>^ 

596^ 

5    0 

7o,¥ 

425 

94X 

566X 

5     3 

67^^ 

404^ 

83^ 

515 

5    6 

643/ 

386-4: 

82 

492^ 

5    9 

61;^ 

369  >^ 

78^ 

472 

6    0 

59 

354 

75;^ 

453^ 

6    3 

56;^ 

340 

72>^ 

435^ 

6    6 

54^ 

32634: 

6934: 

419K 

6    9 

52>^ 

314^ 

67X 

404>^ 

7    0 

50;^ 

303;^ 

65 

396^ 

7    3 

48X 

293 

6234: 

377>^ 

7    6 

47  , 

283X 

60^ 

365>^ 

7    9 

45  >^ 

274 

59 

354 

8    0 

44 

265^ 

57 

343  X 

8    3 

42^ 

257;^ 

55>^ 

333X 

8    6 

A^% 

250 

Rule  for  ^^-inch  Plates. — Divide  4250  by  the  diameter  of  the 
boiler  in  inches ;  the  quotient  is  the  working  pressure,  being  one- 
sixth  of  the  strength  of  the  joints. 

Rule  for  i^-inch  Plates. — Divide  5666-6  by  the  diameter  of  the 
boiler,  and  the  quotient  will  be  the  greatest  pressure  that  the  boiler 
should  work  to  while  new ;  that  is,  one-sixth  of  the  punched  plates. 

We  now  come  to  the  rectangular  forms,  or  flat  surfaces,  which  are 
not  so  well  calculated  to  resist  pressure.  Of  these  we  have  many 
instances :  the  fire-box  of  the  locomotive  boiler,  the  sides  and  flues 
of  marine  boilers,  and  the  flat  ends  of  cylindrical  boilers,  and  other 
boilers  of  weaker  construction.  The  locomotive  boiler  is  generally 
worked  up  to  a  pressure  of  120  lbs.  on  the  square  inch,  and  at  times, 
when  ascending  steep  inclines,  we  have  known  the  steam  nearly  as 
high  as  200  lbs.  on  the  square  inch.  In  a  locomotive  boiler  subject 
to  such  enormous  working  pressure,  it  requires  the  utmost  care  and 
attention  on  the  part  of  the  engineer  to  satisfy  himself  that  the  flat 
surfaces  of  the  fire-box  are  capable  of  resisting  that  pressure,  and 
that  every  part  of  the  boiler  is  so  nearly  balanced  in  its  powers  of 


BOILERS   FOR   STATIONARY   ENGINES.  29 

resistance,  as  that  when  one  part  is  at  the  point  of  rupture,  every 
other  part  is  on  the  point  of  yielding  to  the  same  uniform  force. 
This  appears  to  be  an  important  consideration  in  mechanical  con- 
structions of  every  kind,  as  any  material  applied  for  the  security  of 
one  part  of  a  vessel  subject  to  uniform  pressure,  whilst  another  part 
is  left  weak,  is  so  much  material  thrown  away;  and  in  stationary 
boilers,  or  in  moving  bodies  such  as  locomotive  engines  and  steam 
vessels,  they  are  absolutely  injurious,  at  least  so  far  as  the  parts  Are 
disproportionate  to  each  other,  because  when  maintained  in  motion 
they  become  an  expensive  and  unwieldy  encumbrance.  The  greater 
portion  of  the  fire-boxes  in  locomotive  boilers  have  the  rectangular 
form,  and  in  order  to  economize  heat,  and  give  space  for  the  furnace, 
it  becomes  necessary  to  have  an  exterior  and  interior  shell.  That 
which  contains  the  furnace  is  generally  made  of  copper,  firmly  united 
by  rivets,  and  the  exterior  shell,  which  covers  the  fire-box,  is  made 
of  iron,  and  united  by  rivets  in  the  same  way  as  the  copper  fire-box. 
Now  these  plates  would  of  themselves,  unless  supported  by  rivetted 
stays,  be  totally  inadequate  to  sustain  the  pressure.  In  fact,  with  one- 
tenth  of  the  pressure,  the  copper  fire-box  would  be  forced  inwards 
upon  the  furnace,  and  the  external  shell  bulged  outwards,  and  with 
every  change  of  force  these  two  flat  surfaces  would  move  backwards 
and  forwards,  like  the  sides  of  an  inflated  bladder,  at  the  point  of 
rupture.  To  prevent  this,  and  give  the  large  flat  surfaces  an 
approximate  degree  of  strength  with  the  other  parts  of  the  boiler, 
wrought-iron  or  copper  stays,  i  inch  in  diameter,  are  introduced. 
They  are  first  screwed  into  the  iron  and  copper  on  both  sides  to 
prevent  leakage,  and  then  firmly  rivetted  to  the  exterior  and  interior 
plates.  These  stays  are  from  6  inches  to  4^  inches  asunder,  form- 
ing a  series  of  squares,  and  each  of  these  will  resist  a  strain  of  about 
1 5  tons  before  it  breaks.  Let  us  suppose  the  greatest  pressure  con- 
tained in  the  boiler  to  be  200  lbs.  on  the  square  inch,  and  we  have 
6x6x200=7200  lbs.,  or  31^  tons,  the  force  apphed  to  a  square 
containing  36  square  inches.  Now  as  these  squares  are  supported 
by  four  stays,  each  capable  of  sustaining  15  tons,  we  have  4x15  = 
60  tons  as  the  resisting  powers  of  the  stays ;  but  the  pressure  is  not 
divided  amongst  all  the  four,  but  each  stay  has  to  sustain  that  pres- 
sure, consequently  the  ratio  of  strength  to  the  pressure  will  be  4^ 
to  I  nearly,  which  is  a  very  fair  proportion  for  the  resisting  power 
of  that  part. 

We  have  treated  of  the  sides,  but  the  top  of  the  fire-box  and 


30 


MODERN   STEAM   PRACTICE. 


the  ends  have  also  to  be  protected,  and  there  being  no  other  part 
but  the  circular  top  of  the  boiler  to  which  to  attach  stays,  it  has 
been  found  more  convenient  and  equally  advantageous  to  secure 
these  parts  with  a  series  of  wrought-iron  bars,  from  which  the  roof 
of  the  fire-box  is  suspended,  and  which  effectually  prevents  it  being 
forced  down  upon  the  fire.  It  will  not  be  necessary  here  to  go  into 
the  calculation  of  those  parts.  They  are,  when  rivetted  to  the  dome 
or  Voof,  of  sufficient  strength  to  resist  a  pressure  of  300  to  400  lbs.  on 
the  square  inch.  This  is,  however,  generally  speaking,  the  weakest 
part  of  the  boiler,  with  the  exception  probably  of  the  fiat  ends  above 
the  tubes  in  the  smoke-box,  where  they  are  carefully  stayed.  In 
the  fiat  ends  of  cylindrical  boilers,  and  those  for  marine  purposes, 
the  same  rule  applies  as  regards  construction,  and  the  due  propor- 
tion of  the  parts,  as  in  those  of  the  locomotive  boiler,  must  be  closely 
adhered  to. 

Every  description  of  boiler  used  in  manufactories,  and  also  on 
board  ship,  should  be  constructed  to  stand  at  least  six  times  the 
working  pressure,  or  a  pressure  of  about  500  lbs.  on  the  square  inch; 
and  locomotive-engine  boilers,  which  are  subjected  to  a  much 
severer  duty,  to  about  800  lbs.  per  square  inch.  Internal  flues,  such 
as  contain  the  furnaces  in  the  interior  of  the  boiler,  should  be  kept 
as  nearly  as  possible  to  the  cylindrical  form ;  and  as  wrought-iron 
will  yield  to  a  force  tending  to  crush  it  of  about  one-half  of  what 
would  tear  it  asunder,  the  flues  should  in  no  case  exceed  one-half  of 
the  diameter  of  the  boiler;  and,  with  the  same  thickness  of  plates, 
it  may  be  considered  equally  safe  to  the  other  parts.  In  fact,  we 
should  advise  the  diameter  of  the  internal  flues  to  be  in  the  ratio  of 
I  to2}4,  instead  of  i  to  2  of  the  diameter  of  the  boiler.  Corrugated 
flues  as  now  made  of  iron  or  steel  give  increased  strength. 

THE    STRENGTH    OF    ROUND    BOILERS    WITH    DIFFERENT 
QUALITIES    OF   PLATES. 

When  the  tensile  stress  of  each  boiler-plate  is  not  known  per 
square  inch,  or  the  strain  that  it  will  bear  before  breaking,  to  find 
the  thickness  for  a  certain  diameter,  multiply  the  diameter  in  inches 
by  the  steam  pressure,  dividing  the  product  by  one-sixth  of  the 
ultimate  mean  strength  of  the  plate  per  square  inch,  and  the 
quotient  is  the  thickness.  When  the  boiler  rests  on  brickwork,  add 
^  inch  more.     The  tensile  strain  of  the  best  boiler-plate  is  about 


BOILERS   FOR   STATIONARY   ENGINES.  3 1 

62,544  lbs.,  and  the  worst  34,000  lbs.  per  square  inch.  Taking  one- 
sixth  of  the  mean,  or  8045  lbs. — (this  is  presuming  the  best  plates 
are  used;  if  the  plates  are  of  inferior  quality,  it  is  obvious  the  con- 
stant is  too  high  proportionally,  although  it  may  answer  in  practice 
with  a  parcel  of  the  best  plates  untested) — we  have,  for  a  boiler 
6  feet  6  inches  in  diameter,  and  with  60  lbs.  steam  per  square  inch, 
the  following  result  (the  seams  being  single-rivetted) : — 

-^|^=:-58,  say  T^  inch, 

as  the  thickness,  or  when  set  in  brickwork  say  ^  of  an  inch.     This 
is  allowed  on  account  of  the  corrosion  that  takes  place  with  all  boilers 
resting  on  a  brickwork  foundation.     The  ends  should  be  at  least 
^  inch  more  than  the  calculated  thickness. 
In  another  form  it  may  be  taken  thus — 

P.  Pressure  per  square  inch. 

D.  Diameter  of  boiler  in  inches. 

T.  Thickness  of  plates  in  inches. 

C.  Constants  for  varying  qualities  of  plates. 

Double  Rivetted.  Single  Rivetted. 

C  =  For  Yorkshire  plates  of  best  quality, 7800  6200 

C  =  For  Staffordshire  plates  of  best  quality, 6200  5000 

C  =  For  ordinary  plates, 3700  3300 

2  C 

It  will  be  seen  that  this  formula  gives  a  thickness  of  the  plates 
somewhat  less  than  the  previous  rule,  using  the  best  quality,  a  result 
not  at  all  to  be  desired;  yet  when  the  quality  of  the  plates  is  tested 
by  a  strip  cut  off  each  plate,  one-sixth  of  the  strength  of  the  rivetted 
joints,  as  per  following  table,  may  be  safely  taken  as  the  constant 


T^e  Strongest  Form  and  Proportion  of  Rivetted  y'oints,  as  deduced  from  Experiment 

and  Practice. 


Thickness  of 

Diameters  of 

Length  of  Rivets 

Distance  of  Rivets 

Quantity  of  Lap 

Plates  in  Parts 

Rivets  in 

from  Head 

from  Centre  to 

in  Single  Joints 

of  an  Inch. 

Inches. 

in  Inches. 

Centre  in  Inches. 

in  Inches. 

•i8=t\ 

•38) 

•88^ 

1-25  1 

6 

1-25) 

•25  =  i 

■5°  (2 

•63  r 

I-I3 

i-Soi 

1  -50  y  6 

•31=  A 

1-38 

1-63  1 

5 

1-88  \ 

■37=1 

'IH 

1-63 

U-5 

175! 

2  'oo    5  '5 

T=I 

•81 

2-25 

2'00 

2-25  ) 

•62=1 

•94M-5 

275 

2-50 

4 

275  U'S 

75  =  i 

I-I3) 

3 '25  J 

3-00 

3-25  ) 

32 


MODERN   STEAM   PRACTICE. 


For  double-rivetted  joints,  add  two-thirds  of  the  depth  of  the 
single  lap.  Where  great  strength  is  desirable  this  form  of  joint 
should  always  be  adopted.  It  will  be  seen  from  the  following  table 
that  the  double-rivetted  joints  retain  their  resisting  power,  while  the 
single-rivetted  joints  lose  about  one-fifth  of  the  actual  strength  ot 
the  plates. 

The  figures  2,  I'S,  4'S,  6,  5,  &c.,  given  in  the  preceding  table  are 
multipliers.  These  multipliers  are  considered  as  proportionals  of 
the  plates;  thus,  supposing  we  take  }i  of  an  inch  as  the  thickness 
of  plates,  we  have  simply  to  multiply  the  thickness  by  the  number 
to  find  the  proportionate  quantities  to  form  the  strongest  joint: — 

Inches. 
*37S  ^2    =    750  diameter  of  rivet. 
•375  X  4*5  =  I  "687  length  of  rivet. 
•375  X  5     =1  "875  distance  between  rivets. 
'375  X  5  "5  =2 '062  quantity  of  lap,  single  rivetted. 
'375  X  9'i  =3'4i2  quantity  of  lap,  double  rivetted. 

It  will  be  seen  that  the  dimensions  thus  found  nearly  agree  with 
the  dimensions  in  the  preceding  table,  which  are  practically  correct. 

Boilers  are  now  being  made  of  steel:  as  made  by  the  Siemens  or 
Bessemer  process,  the  tensile  strength  is  about  29  tons  per  square 
inch,  and  the  elastic  strength  appears  to  lie  within  11  to  16  tons 
per  square  inch.  Test  pieces,  10  inches  long,  give  an  elongation  of 
28  per  cent,  with  a  contraction  of  area  of  about  49  per  cent. 
Punching  the  rivet  holes  weakens  the  metal  by  about  30  per  cent; 
the  strength  can,  however,  be  restored  by  annealing.  Drilling  the 
holes  does  not  seem  to  affect  the  strength.  By  the  use  of  steel 
the  weight  of  boilers  has  been  reduced  about  10  per  cent  For 
further  reference  to  manufacture  and  strength  of  steel  see  section  on 
Shipbuilding,  p.  960. 


Mean  Strength  of  Plates  in  the  direction  of  and  across  the  Fibre  {Fairbairn). 


Breaking  Weight 
in  the  direction  of 
the  Fibre,  in  tons 
per  square  inch. 

Breaking  Weight 

across  the   Fibre, 

in  tons  per  square 

inch. 

Yorkshire  Plates 

25720 
22760 
21-680 
22-826 
19-563 

27-490 
26-037 
18-650 
22  -OOO 
21  010 

Do.         do 

Derbyshire  do 

Shropshire  do 

Staffordshire  do 

Mean 

22-509 

23-037 

BOILERS   FOR   STATIONARY  ENGINES. 
Tensile  Strength  of  Single  and  Double  Rivetted  Plates. 


33 


Cohesive  Strength  of 

Strength  of  Single  Rivetted 

Strength  of  Double  Rivetted 

Plates. 

Joints,  of  equal  Section 

Joints,  of  equal  Section 

Breaking  Stress  in  Lbs. 

to  the  Plates,  taken  through 

to  the  Plates,  taken  through 

per  Square  Inch. 

the  Line  of  Rivets. 

the  Line  of  Rivets. 

57,724 

45,743 

52,352 

61,579 

36,606 

48,821 

58,322 

43,141 

58,286 

50,983 

43,515 

54,594 

51,130 

40,249 

53,879 

49,281 

44,715 

53,869 

43,805 

37,161 

47,062 

Mean,   52,485 

4i,S9C 

53.633 

Area  of  boiler  stays  =  — ^,  where  A=area  of  surface  of  plate 

held  by  one  stay,  and  /  and  /  being  the  pressure  and  tenacity  re- 
spectively. 

The  following  value  of  plates  may  be  fairly  assumed  with  those 
of  joints:— 

Plates 100 

Double  Rivetting 70 

Single  Rivetting 56 

In  a  series  of  experiments  by  Napier  the  tensile  strength  of  iron 
plates  averaged  from  56,735  to  41,743  lbs.  per  square  inch. 

Weight  of  a  Square  Foot  of  Wrought-iron  Plate  from  -^  to  i  ijzch  in  Thickness. 


Thickness 
in  inches. 

Weight 
in  lbs. 

Thickness. 

Weight. 

7\ 

1-25 

1-4-1 

21-25 

T^ 

2-5 

-h 

22-5 

T?  +  '57 

375 

TB-  +  "5'J 

2375 

■3- 

5- 

S 

25- 

i  +  TfV 

6-25 

■ff  +  irs 

26-25 

1^ 

7-5 

w 

27-5 

^  +  A 

875 

1 1  1    1 

28-75 

T 

lo- 

1 

30- 

\^i^ 

1 1  "25 

h^-h 

31-25 

.    1^ 

12-5 

T^ 

32-5 

Tf  +  TI 

1375 

TB-  +  "r5 

3375 

¥ 

15- 

\ 

35- 

l  +  A 

16-25 

I  +  T5 

36-25 

7 

17-5 

1  5 

37-5 

T^  +  T^ 

1875 

15    1     1 

38-75 

"J 

20  • 

I 

40- 

Weight  of  Angle  Iron,  in  Lbs.  per  Lineal  Foot. 

Breadth  in  inches \%,  1%,  i^,  2,  2%  2}^,  2^,   3,    3^,    3>^. 

■Weight  per  foot  in  lbs I'S,  2-7,  3*3,  3-9,  5,  6-5,  8-3,  10-4,  117,  14. 


34  MODERN    STEAM    PRACTICE. 

Weight  of  a  Lineal  Foot  of  Square  and  Round  Bar  Iron,  in  Lbs. 


Size. 

Square 
Bar. 

Round 
Bar. 

Size. 

Square 
Bar. 

Round 
Bar. 

Size. 

Square 
Bar. 

Round 
Bar. 

\ 

•209 

•164 

I^ 

5-25 

4-09 

3 

30-07 

23-60 

5 

•326 

•256 

m 

6-35 

4-96 

VA 

35-2S 

27-70 

3 

•470 

•369 

1^2 

7-51 

5  "90 

r/2 

40-91 

32-13 

7 

•640 

•502 

iM 

8-82 

6  92 

?,% 

46-97 

36-89 

1 
■5 

•835 

•656 

vy. 

10-29 

803 

4 

5  3 '44 

41-97 

9 

1-057 

-831 

lyk 

11-74 

9-22 

A% 

60-32 

47-38 

6 

■5 

I-305 

1-025 

2 

13-36 

10-49 

4/2 

67-63 

53-12 

I  1 

I '579 

I -241 

2% 

1508 

11-84 

aK 

75 '35 

59-18 

3. 

1-879 

1-476 

2% 

16-91 

13-27 

5 

83-51 

65-58 

1  3 

2-205 

1-732 

2^ 

18-84 

14-79 

S% 

9246 

72-30 

7 

2-556 

201 1 

2/2 

20-87 

16-39 

5/2 

101-63 

79-35 

1  5 
Iff 

2-936 

2-306 

2)i 

23-11 

18-07 

S% 

114-43 

86-73 

I 

3'34 

2-62 

2% 

25-26 

19-84 

6 

120-24 

94  43 

li 

4-22 

3-32 

2-A 

27-61 

21-68 

Surface  of  Tithes  per  Lineal  Foot, 

in  Square  Feet. 

Diameter 

Surface    .. 

inch 

% 
•1636 

•1963 

•2291 

I 
•2618 

1% 
•2945 

•3270 

1% 
•3599 

■3927 

Diameter 

inch 

1% 
•4253 

•4580 

1% 
•4906 

2 

•5233 

2% 
•5890 

2>^ 
-6544 

2H 
•7199 

3 

•7854 

Weight 

per  Foot 

in  Lbs. 

and  Decimal  Parts  ofLron,  Brass 

and  Copper  Tubes. 

Inches 

Birming- 

Inches 

Birming- 

External 

ham  Wire 

Iron. 

Brass. 

Copper. 

External 

ham  Wire 

Iron. 

Brass. 

Copper. 

Diameter. 

Gauge. 

Diameter. 

Gauge. 

^% 

13 

1-402 

1-529 

1-627 

3^ 

9 

5-640 

6-148 

9-500 

iVi 

13 

1-528 

1-665 

1-772 

4  , 

8 

6-652 

7-250 

7-716 

^% 

13 

1-653 

I -801 

1-917 

A% 

8 

7-087 

7-724 

8-220 

m 

12 

2-024 

2-206 

2-347 

A% 

8 

7-497 

8-17I 

8-696 

2 

12 

2-168 

2-363 

2-514 

aH 

8 

7-953 

8-668 

9-225 

2%  ■ 

12 

2-311 

2-513 

2 -680 

5 

7 

9120 

9-940 

10-579 

2X 

II 

2-687 

2-928 

3-116 

5X 

7 

9-596 

10-459 

III3I 

2% 

II 

3-002 

3-272 

3-482 

S% 

7 

10-089 

10-997 

1 1  -603 

2% 

10 

3 -68s 

4-016 

4-274 

sH 

7 

10-539 

11-487 

12-225 

3 

ID 

4-038 

4-401 

4-684 

6 

6 

12-371 

13-484 

14-350 

V4 

9 

4826 

5-260 

5 -.598 

7 

6 

14-168 

15-444 

16-435 

Z% 

9 

5-215 

5-684 

6  049 

PROPORTIONS   FOR   PLAIN   LAND   BOILERS. 

Shell. — Having  pointed  out  the  principles  to  be  observed  in  con- 
struction, -we  -will  proceed  to  give  the  proportions  generally  adopted 
in  Steam  boilers.  For  each  nominal  horse-power  make  an  allow- 
ance of  I  cubic  yard,  or  27  cubic  feet  capacity ;  this  is  simply  the 


BOILERS   FOR   STATIONARY   ENGINES  35 

cubical  contents  of  the  shell,  with  or  without  inside  flues.  Sup- 
posing, for  the  sake  of  illustration,  a  Cornish  boiler  of  40  nominal 
horse-power  was  required,  multiply  the  horse-power  by  27  cubic 
feet,  and  the  result  will  be  the  cubical  contents,  thus — 

40  X  27  =  1080  cubic  feet. 

Length  and  Diameter. — The  length  of  the  boiler  should  be  about 
three  and  one-half  times  the  diameter  for  moderate  power,  or  up  to 
about  20  horse-power  inclusive;  above  that  size  five  times  the 
diameter  can  be  adopted — a  little  more  or  less  can  do  no  harm.  To 
find  the  diameter,  multiply  1080,  the  cubical  contents  required,  by 
the  constant  1*28,  dividing  the  result  by  the  proportion  of  the  dia- 
meter to  the  length,  say  five  times,  and  the  cube  root  of  the  quotient 
will  be  the  diameter,  which,  multiplied  by  5,  gives  the  length  of  the 
boiler  nearly. 

io8oxi*28        3/    ^^     o  /!r  -  »     - 

=v^276-48  =  say  6-5x5  =  32 'S. 


The  length  of  the  boiler,  in  roun(i  numbers,  is  32*5  feet,  and 
6"5  feet  in  diameter.  To  check  the  calculation,  the  area  of  6*5  feet 
in  diameter  is  33'i8  square  feet  X  32-5  =  I078'35  cubic  feet,  within 
a  trifle  of  what  is  required. 

Heating  Surface,  Fire-grate,  and  Flue  Area. — The  heating  surface 
should  not  be  less  than  i  square  yard,  or  9  square  feet,  per  nominal 
horse-power;  but  in  ordinary  boilers  it  will  be  found  that  more  than 
this  can  be  conveniently  got.  The  area  of  the  fire-grate,  when  the  fur- 
nace is  underneath  the  boiler,  should  be  i  square  foot,  and  when  the 
furnace  is  in  a  flue,  forming  part  of  the  boiler,  75  of  a  square  foot  will 
be  sufiicient,  per  nominal  horse-power.  The  length  of  the  fire-grate 
should  never  exceed  7  feet.  When  the  furnaces  are  placed  inside  of 
the  boiler,  for  small  diameters,  the  inside  flues  should  be  2f  feet  6  inches 
in  diameter,  and  certainly  not  less  than  2  feet  3  inches.  When  smaller 
than  this,  the  fires  do  not  burn  well,  and  they  are  troublesome  to 
fire;  for  large  diameters  of  boilers,  the  furnace  flues  can  be  3  feet 

3  inches  in  diameter.  The  area  of  the  furnace  flues  should  be 
about  28  square  inches  per  nominal  horse-power,  a  little  more  doing 
no  harm ;  thus  for  40  horse-power,  we  have  for  two  furnaces — 

40  X  28  =  1 120  -j-  2  =  560  square  inches, 

equal  say  2  feet  3  inches  diameter  for  each  flue  in  the  boiler,  and 

4  feet  6  inches  as  the  sum  of  the  width  for  both;   thus,  for  the 


36  MODERN   STEAM   PRACTICE. 

length  of  the  grate,  making  an  allowance  of  75  of  a  square  foot  per 
nominal  horse-power,  we  have — 

^^f^  =  6-6  feet  in  length. 

The  area  over  the  bridge  is  generally  about  18  square  inches  per 
nominal  horse-power. 

Water  and  Steam  Room. — For  boilers  with  hemispherical  ends, 
the  water  should  fill  the  boiler  two-thirds  of  its  diameter,  thus  leav- 
ing one-third  as  steam-room.  For  Cornish  arrangement  with  two 
furnaces  (otherwise  known  as  the  Butterly  boiler)  the  water  generally 
fills  the  boiler  three-fourths  of  its  diameter,  the  remainder  being  the 
steam-room.  One  foot  height  of  water  over  the  furnaces  is  allowed ; 
when  one  furnace  is  adopted  the  steam-room  in  the  boiler  can  be  in- 
creased, and  it  is  always  advisable  to  have  steam  domes  fitted  to 
the  top. 

RELATIVE   VALUE    OF    HEATING    SURFACE. 

Horizontal  surface  above  the  flame =  i*0 

Vertical  „  ,,  =0-5 

Horizontal  surface  below  the  flame, o'O 

Tubes  and  flues =  iX  of  their  diameter. 

BOILER   FOUNDATIONS. 

With  the  foregoing  proportions  we  may  now  commence  to  lay  out 
the  boiler  foundations.  The  boilers  are  generally  ordered  in  dupli- 
cate, so  that  no  stoppage  may  occur  in  the  event  of  one  of  them 
requiring  repairs;  indeed,  when  deposits  rapidly  form  from  impurities 
in  the  water,  frequent  inspection  is  necessary,  periodical  scaling  and 
cleaning  out  being  required.  After  the  ground  is  excavated,  a  bed 
of  concrete*  is  laid  all  over,  on  which  is  built  the  superstructure  for 
carrying  and  bedding  the  boiler  thereon.  The  Cornish  or  London 
boiler,  with  inside  furnaces,  rests  on  a  mid  wall,  having  cast-iron 
supports  imbedded  in  the  middle  wall,  and  should  be  of  sufficient 
height  to  leave  about  3  feet  4  inches  from  the  stoking-floor  to  the 
dead  plates  on  the  furnace  front.  The  boiler  is  surrounded  with 
what  is  technically  termed  a  wheel-flue,  that  is  to  say,  the  flame  and 
the  heated  gases  pass  through  the  internal  furnaces  and  the  back 
flues  contained  in  the  boiler,  then  wheel  round  at  the  end,  and  return 
to  the  front — along  one  side,  and  pass  along  the  other  side  nearest 
the  chimney,  an  opening  being  left  in  the  mid  wall  at  the  bottom 


BOILERS  FOR  STATIONARY  ENGINES. 


37 


for  the  flame  and  the  gases  to  cross  from  one  side  of  the  boiler 
to  the  other  side  nearest  the  chimney,  and  they  escape  into  a  flue 


J^ 


D  D,  Boilers. 

E,  Furnaces,  Flues,  and 
Chimney. 

F,  Steam  receiver. 
G  G,  Stop  valves. 
H,  Manhole. 
1 1,  Dampers. 
K,  Safety  valve. 


i8.  — Foundations  for  Cornish  or  London  Boilers.     A,  End  view. 
Section  showing  direction  of  the  Flues.     C,  Longitudinal  section. 

common  to  both  boilers,  and  thence  find  their  way  into  the  chimney 
placed  at  the  end  of  this  main  terminal  flue.  The  flues  round  the 
boiler  should  have  the  necessary  area,  and  sufficient  room  left  at 


38  MODERN   STEAM   PRACTICE. 

the  bottom  for  the  convenience  of  executing  repairs  and  cleaning  out 
the  flues.  To  resist  the  action  of  the  flame  the  flues  are  Hned  with 
fire-brick,  and  at  the  front  of  the  building  openings  are  left,  which 
are  fitted  with  cast-iron  doors  for  the  convenience  of  periodical 
inspection  of  the  boiler. 

Damper-plates  are  fitted  to  each  boiler.  They  are  simply  cast- 
iron  plates,  sliding  in  suitable  frames  of  cast-iron  imbedded  in  the 
building.  The  damper-plate  has  a  "snug"  cast  on  for  attaching  a 
chain  provided  with  a  back  balance  weight,  the  chain  passing  over 
a  pulley,  carried  up  by  means  of  a  cast-iron  pedestal,  securely  fast- 
ened down  to  a  large  stone  imbedded  in  the  top  courses  of  the  brick- 
work. Sometimes  the  revolving  pulley  can  be  carried  up  from  a 
plate  and  pin  secured  to  the  wall  of  the  boiler-house.  To  protect 
the  top  of  the  boiler  from  radiation,  it  is  arched  over  with  fire-bricks, 
the  space  between  the  boiler  and  the  brick  arch  being  filled  in  with 
ashes,  and  sometimes  sand  is  used. 

The  walls  of  the  boiler-house  are  covered  over  with  a  suitable 
wrought-iron  roof,  having  a  ventilator  at  the  top  for  carrying  away 
any  waste  steam  that  may  blow  off.  The  arrangement  of  the  flues 
just  described  will  suit  all  boilers  having  internal  furnaces;  but  when 
the  boiler  is  constructed  with  one  internal  small  flue,  it  is  preferable 
to  form  the  furnace  underneath. 

Now  for  cylindrical  arrangements,  having  hemispherical  ends,  this 
class  of  steam-generators  is  usually  longer  in  proportion  to  the  dia- 
meter than  the  Cornish  type;  in  some  instances  six  and  three-quarter 
times  the  diameter  has  been  adopted.  The  buildings  are  very  differ- 
ent from  the  foregoing  example.  The  same  height  from  the  stoking- 
fioor  to  the  dead-plate  is  allowed,  namely,  3  feet  4  inches.  This 
plate  is  made  long,  so  that  the  coal  may  cake  before  being  pushed 
amongst  the  incandescent  fuel,  this  eff'ecting  a  considerable  economy 
when  properly  attended  to.  A  height  of  about  2  feet  4  .inches  is 
allowed  in  large  boilers,  from  the  top  of  the  fire-bars  to  the  under- 
side of  the  boiler;  and  the  flues  are  arranged  on  the  wheel  principle, 
as  in  the  Cornish  type,  with  this  difference,  that  the  flame  passes 
underneath  the  boiler,  and  then  ascends  at  the  back,  all  round,  and 
thence  up  the  chimney.  There  is  a  combustion  chamber  formed  at 
the  back  of  the  bridge,  at  the  end  of  the  fire-bars  furthest  from  the 
front,  the  flame  as  it  were  hanging  at  the  hollow  left  in  the  bottom 
flue,  thus  making  the  bottom  surface  of  the  boiler  very  effective  as 
heating  surface.  This  recess  likewise  serves  the  purpose  of  collecting 


BOILERS   FOR   STATIONARY   ENGINES. 


39 


both  the  ashes  and  the  soot  that  may  be  drawn  over  by  the  draught, 
and  which  are  raked  out  through  a  hole,  fitted  with  a  movable  door, 


DD,  Boilers. 

E,  Furnace,  Flues,  and 
Chimney. 

F,  Steam  receiver. 
G  G,  Stop  valves. 
H,  Manhole. 

I  I,  Dampers. 
K,  Safety  valve. 
L,  Float. 
M,  Feed-pipe. 
N,  Blow-off  tap. 


ji Fig.  19.— Foundations  for  Cylindrical  Boilers.     A,  End  view. 

[_ J      B,  Section  showing  direction  of  the  Flues.      C,  Longitudinal  section. 

placed  at  the  bottom  of  the  bridge.     The  boiler  is  usually  set  with 
a  dip  towards  the  back  of  /s  inch  to  the  foot,  so  that  the  sludge 


40  MODERN   STEAM   PRACTICE. 

may  collect  at  the  part  farthest  from  the  fire.  A  plug-valve  is 
fitted  to  the  underside  of  the  boiler,  to  which  is  attached  a  pipe 
leading  into  a  drain  left  in  the  building;  by  this  means  the  water 
flows  away  when  the  boilers  are  blown  off  The  buildings  are 
generally  hollowed  out  to  lighten  the  structure,  and  the  boiler  is 
fitted  with  brackets,  bolted  to  the  top,  so  as  partly  to  take  the 
weight;  but  the  main  support  is  at  the  sides  of  the  furnace,  the 
furnace  walls  being  carried  up  from  the  bed ;  but  at  times  when  the 
sides  of  the  furnace  are  undergoing  repair,  the  top  brackets  take  the 
weight.  All  the  flues  must  have  sufficient  area,  as  likewise  doors 
must  be  left  in  the  brickwork  for  cleaning  them  out;  the  height 
from  the  top  of  the  bridge  to  the  under  side  of  the  boiler  is  gener- 
ally about  1 8  inches.  The  fittings  are  just  the  same  as  for  the 
Cornish  boiler,  having  a  wrought -iron  steam-chest  connecting  all 
the  boilers,  provided  with  a  stop -valve  to  each  boiler,  with  the 
addition  of  a  stone  float  and  back-balance  for  indicating  the  height 
of  the  water  inside  of  the  boiler.  No  float  is  required  for  the 
Cornish  class,  as  the  ordinary  water-gauge  is  fitted  to  the  front 
end ;  hemispherical-ended  boilers,  however,  can  have  a  gauge-glass 
in  front,  with  suitable  pipe  connections  passing  through  the  brick- 
work. The  safety-valve  is  placed  on  the  top,  at  the  fire -end, 
then  the  stop-valves,  next  the  float  of  stone  with  weight,  then  the 
manhole,  and  the  feed-pipes  at  the  back  of  the  boiler,  all  placed  on 
the  centre  line. 

We  will  now  notice  the  arrangements  for  one  small  internal  flue. 
The  furnace  is  placed  underneath  the  boiler,  the  flame  acting  on  the 
bottom,  and  then  through  the  small  tube,  which  carries  it  to  the 
front,  the  flame  splitting  as  it  were  at  the  front  end,  passing  down 
each  side,  and  meeting  at  the  back  in  one  central  flue,  in  the  same 
line  as  the  centre  of  the  boiler ;  this  is  required  so  that  the  draught 
may  be  equalized  in  the  side  flues,  as  the  heated  gases  have  always 
a  tendency  to  take  the  shortest  passage  into  the  chimney.  Some 
boilers  of  the  cylindrical  type,  with  hemispherical  ends,  are  hung 
from  the  top  with  brackets,  having  no  support  underneath,  the 
flame  acting  on  the  bottom  and  the  sides,  and  then  passing  directly 
into  the  chimney ;  this  is  not  so  good  an  arrangement  as  the  return 
flues,  as  the  flame  and  the  heated  gases  have  no  time  to  act  on  the 
surfaces,  unless  boilers  of  inconvenient  length  are  adopted.  The 
furnace  bars  should  be  made  in  suitable  lengths,  having  a  thick- 
ness  of  y^  inch   at   the   top,  and   ^  inch   at   the   bottom,  with 


BOILERS   FOR   STATIONARY   ENGINES. 


41 


projections   at  the  ends,  and   the   middle   of  the  top,  the   open- 
ings  between  the  bars  varying   from  ^  to  ^  inch,  to  suit   soft 


B 


»<5 

0 

H 

DD,  Boilers. 

E,  Furnace,  Flues,  and 

Chimney. 

F,  Steam  receiver. 
GG,  Stop  valves. 
H,  Manhole. 

1 1,  Dampers. 
K,  Safety  valve, 
L,  Float. 
M,  Feed  pipe. 


Fig.  20. — Foundations  for  Boilers  with  small  Internal  Flue.     A,  End  view.     B,  Section  showing 
direction  of  Flue.     C,  Longitudinal  section. 

and  hard  coal,  the  depth  of  the  bars  at  the  middle  being  from 
33^^  to  4  inches. 


AREA   AND   DIMENSIONS   OF   CHIMNEY. 

To  determine  the  area  of  tne  top  of  the  chimney  for  a  given  con- 
sumption of  coal  per  hour,  the  average  for  Cornish  boilers  being 
10  lbs.  per  nominal  horse-power,  multiply  the  number  of  lbs.  con- 
sumed per  hour  by  12,  and  divide  the  product  by  the  square  root 
of  the  height  of  the  chimney  in  feet  (the  usual  height  for  factory 


42  MODERN    STEAM   PRACTICE. 

chimneys  being  80  feet),  and  the  quotient  is  the  area  at  the  top  of  the 
chimney,  thus  for  /to  nominal  horse-power — 

-"  "^'2^  =  5  39.  say  26  inches  diameter, 

or  23  inches  square  at  the  top.  It  is  always  preferable  to  make  an 
allowance  over  and  above  this  for  the  convenience  of  leading  other 
flues  into  it.  For  a  chimney  80  feet  in  height  the  brickwork  should 
be  divided  into  three  courses:  for  30  feet  height  from  the  bottom  two 
bricks  in  thickness,  the  next  course  one  and  a  half  brick  in  thick- 
ness, and  the  remainder  one  brick  thick.  For  each  25  feet  added 
in  height  the  brickwork  at  the  bottom  should  be  increased  one- 
half  brick  in  thickness.  The  batter  or  the  slope  of  the  side  is  usually 
0'3  of  an  inch  to  the  foot.  Thus,  with  26  inches  inside  diameter  at 
the  top,  the  bottom  of  the  chimney  would  be  92  inches  external 
diameter,  while  that  of  the  top  would  be  44  inches.  Should  the 
internal  diameter  at  the  top  require  to  be  54  inches  and  upwards, 
the  top  course  should  be  one  and  a  half  brick  in  thickness,  and  the 
bottom  courses  in  proportion.  The  inside  at  the  bottom  is  lined 
with  fire-bricks,  leaving  a  space  of  one  inch  between  the  inner  lining 
and  the  main  building,  and  is  carried  up  to  a  height  of  15  feet  from 
the  bottom.  For  a  chimney  80  feet  in  height  the  foundation  should 
be  at  least  5  feet  in  depth,  laid  on  a  bed  of  concrete  2  feet  in  thick- 
ness, but  this  will  depend  on  the  soil ;  on  sand  or  gravel  this  bed  will 
be  quite  sufficient,  but  of  course  some  soils  require  the  foundation 
to  be  carried  down  to  a  firm  bed.  In  marsh  land,  and  even  for  the 
Colonies,  wrought-iron  chimneys  may  be  used  with  advantage,  but 
brick  chimneys  are  to  be  preferred.  The  best  temperature  for  an 
efficient  chimney  draught  is  about  600°  Fahr. 

SMOKE   PREVENTION. 

Although  the  distance  between  the  fire-bars  varies  from  ^  to 
^  inch,  allowing  a  good  volume  of  air  underneath'  the  grate,  so 
essential  for  perfect  combustion,  other  means  must  be  taken  to  con- 
sume the  gaseous  constituents  thrown  off  from  coal  when  in  the  semi- 
incandescent  state;  the  simplest  and  most  effectual  way  of  doing 
this  is  by  admitting  a  current  of  air  through  a  series  of  small  holes 
drilled  through  the  furnace  door,  thus  supplying  the  common  oxygen 
contained  in  the  atmosphere,  and  of  which  we  have  an  unlimited 
command.  Many  schemes  have  been  brought  forward  from  time 
to  time  to  consume  the  gases  evolved  before  a  dense  mass  of  smoke 


BOILERS   FOR   STATIONARY   ENGINES.  43 

is  formed  in  the  flues,  for  if  the  gases  are  not  consumed  before  reach- 
ing the  flues,  it  is  impossible  to  burn  the  smoke  with  the  ordinary- 
arrangements ;  but  those  who  are  under  the  impression  that  smoke, 
or  at  least  what  we  term  smoke,  cannot  be  burned  when  once  formed, 
labour  under  a  sad  mistake,  for  the  densest  volume  passing  through 
a  regenerative  furnace  is  effectually  consumed. 

We  will  take  the  Butterly  boiler,  having  two  internal  flues  or  fur- 
naces meeting  in  one  combustion  chamber  at  the  back  of  the  bridge: 
fire  both  of  these  furnaces  at  one  and  the  same  time,  and  dense 
volumes  of  smoke  will  be  seen  issuing  from  the  top  of  the  chimney; 
the  smoke  is  formed  in  the  furnace,  and  passes  over  the  bridge. 
Now  this  arrangement,  with  careful  firing,  in  a  great  measure  prevents 
smoke  issuing  from  the  chimney.  One  fire  should  be  bright  while 
the  other  one  is  dull,  or  in  the  act  of  firing,  and  what  is  the  conse- 
quence.-* the  combustion  chamber  is  in  a  perfect  glow,  from  the  bright 
fire;  and  the  smoke  evolved  by  the  dull  one  is  effectually  consumed 
by  the  other.  This  simple  fact  is  half  of  the  battle;  careful  firing 
is  the  best  and  most  economical  means  for  the  prevention  of  smoke; 
so  by  alternately  firing  little  or  no  smoke  is  seen  issuing  from  the 
top  of  the  chimney.  Such  practice  every  good  fireman  is  perfectly 
conversant  with. 

As  hydrogen  is  the  main  element  in  the  gases  evolved,  and  by 
the  admixture  of  the  oxygen  of  the  atmosphere  flame  is  produced; 
and  as  neither  hydrogen  nor  oxygen  can  burn  of  itself,  it  remains  for 
us  to  supply  a  current  of  air,  so  as  to  obtain  the  most  economical 
result  from  the  fuel.  With  the  common  blow-pipe  an  intense  heat 
is  obtained  by  simply  blowing  a  current  of  air  through  a  flame  of 
gas,  or  rushes,  as  used  by  the  gasfitter.  And  in  the  smelting  fur- 
nace air  is  forcibly  blown  through  a  coil  of  pipes,  surrounded  and 
inclosed  in  a  furnace,  the  air  is  thus  intensely  heated,  and,  indeed, 
will  melt  a  bar  of  lead  before  it  is  admitted  into  the  smelting  fur- 
nace; this  is  termed  the  '' Jiot  blast','  and  is  familiar  to  all  metallur- 
gists. Were  it  not  for  the  complication  entailed,  this  method  would 
be  by  far  the  best  plan  that  could  be  adopted  for  steam  boilers,  but 
such  an  intense  heat  is  not  at  all  desirable,  for  should  the  water  in 
the  boiler  fall  below  the  working  level,  the  plates  would  get  intensely 
hot,  and  an  explosion  would  be  the  inevitable  result;  so  a  moderate 
measure  of  heated  air  is  all  that  is  required. 

A  very  simple  plan  for  introducing  heated  air  is  by  arranging 
small  pipes,  fixed  to  the  front  plate  of  the  boiler,  as  in  the  double 


44  MODERN   STEAM  PRACTICE. 

furnace  Lancashire  class,  the  pipes  passing  through  the  water  space 
to  the  combustion  chamber  plate,  through  which  they  are  securely 
rivetted,  or  clenched  over.  Thus  a  current  of  hot  air  passes  through 
the  tubes,  mixing  with  the  flame  and  gases  in  the  combustion 
chamber,  so  that  when  the  fires  are  properly  attended  to,  as  with  all 
arrangements  introduced  for  the  prevention  of  this  nuisance  they 
must  be,  little  or  no  smoke  will  appear  at  the  top  of  the  chimney. 
The  introduction  of  heated  air  into  the  combustion  chamber  after 
the  smoke  or  gases  have  passed  the  bridge,  seems  mainly  to  keep  up 
the  temperature  of  the  flues,  by  the  admixture  of  the  oxygen  of  the 
atmosphere  with  the  flame  in  the  combustion  chamber;  this  plan, 
where  it  can  be  conveniently  applied,  should  always  be  adopted. 
As  before  stated,  vertical  boilers  are  so  fitted  with  a  series  of  small 
air-tubes  all  round  the  fire-box,  inclining  downwards,  thus  the  air 
freely  mixes  with  the  live  coal.  In  former  years  some  persons 
scouted  the  idea  of  consuming  the  smoke  after  passing  the  bridge; 
the  fact  of  our  now  being  able  to  do  so  speaks  for  itself  Some 
may  term  it  gas  before  it  has  passed  the  bridge;  but  what  we 
plainly  see  in  the  furnace  we  denominate  smoke. 

For  single  furnaces  a  very  different  arrangement  is  adopted, 
the  smoke  being  consumed  in  the  furnace:  the  fire-door  is  perfor- 
ated with  a  number  of  small  holes  ^  inch  in  diameter,  drilled 
closely  together.  It  seems  impossible  to  give  the  exact  number  of 
holes  to  suit  all  furnaces,  as  the  same  furnace,  with  different  kinds 
of  coal,  requires  more  or  less  openings,  as  the  case  may  be,  and  even 
the  same  furnace  often  requires  more  or  less  air  with  the  same  kind 
of  coal ;  this  may  be  owing  to  the  temperature  of  the  atmosphere,  or 
which  way  the  wind  is  blowing;  if  blowing  in  such  a  direction  as  to 
fan  the  fire,  as  in  the  forward  boilers  for  marine  purposes,  less  air 
will  do  at  the  furnace  door.  Thus  it  is  imperative  to  have  a  great 
number  of  holes,  say  5  to  6  square  inches  for  every  foot  of  fire-grate 
surface ;  they  should  be  covered  with  a  regulator,  or  movable  disc- 
plate, with  corresponding  holes  for  regulating  the  supply;  some 
adopt  slits  instead  of  round  holes,  but  the  latter,  or  jet  system,  is  by 
far  the  best,  as  it  distributes  the  air  equally  amongst  the  gases  in 
the  furnace.  This  plan  necessitates  regulation  by  the  damper. 
Should  no  steam  be  required,  or  the  engine  not  working,  or  even 
when  the  fireman  is  trimming  the  fire,  the  damper  can  be' shut,  check- 
ing the  draught  for  a  time;  the  smoke  remains  in  the  furnace,  or  is 
slowly  consumed  there,  thus  preventing  it  issuing  at  the  chimney  top. 


BOILERS   FOR   STATIONARY   ENGINES.  45 

Another  plan  for  consuming  the  smoke  is  attained  by  blowing 
superheated  steam  through  a  number  of  minute  apertures  placed 
at  the  front  of  the  furnace ;  with  high-pressure  steam  in  the  boilers ; 
this  plan  works  well,  so  long  as  the  apparatus  remains  in  good 
order.  The  steam  requires  to  be  dry  before  it  is  sprayed  into  the 
furnace  in  minute  jets  above  the  grate.  The  steam  from  the  boiler 
is  made  to  flow  through  a  coil  of  pipes  placed  in  the  fire-brick  bridge, 
and  then  passes  through  a  pipe  laid  across  the  furnace  front,  fitted 
with  nozzles  having  holes  j-V  inch  in  diameter;  the  pipe  is  fitted 
with  a  plug-valve  to  regulate  the  supply  to  the  nozzles,  the  furnace 
door  being  provided  with  a  number  of  air  holes,  the  superheated 
steam  is  turned  on,  causing  a  powerful  current  of  air  to  pass  through 
the  fire  door,  and  before  mixing  with  the  gases  in  the  furnace  is 
distributed  with  the  steam  jets  into  minute  atoms,  and  we  may 
say  the  mere  forcing  of  the  atoms  driving  the  oxygen  through 
and  between  the  live  coal,  produces  complete  combustion,  with 
great  economy  in  fuel.  This  is  much  better  than  any  plan  we 
know  of,  from  the  fact  that  fuel  will  burn  with  this  arrangement 
that  would  be  entirely  worthless  in  ordinary  furnaces.  By  the  use 
of  the  jets  of  superheated  steam  all  the  waste  cinders  from  the 
smithy  can  be  utilized,  and  dross  or  small  coals  eff"ectually  burned, 
without  the  smoke  nuisance;  but  we  unhesitatingly  give  as  our 
opinion,  that  unless  the  attendant  sees  that  the  furnace  is  kept  in 
proper  trim,  firing  with  the  least  quantity  of  coal,  oft  times  replen- 
ished, that  all  the  refinements  for  the  prevention  of  smoke  will  not 
attain  the  desired  object,  for  careful  firing  is  the  main  secret  to 
arrive  at. 

SYSTEMS    OF   TUBING. 

The  triangular  and  square  systems  of  tubing  have  certain  advan- 
tages as  well  as  disadvantages.  With  the  former,  almost  used 
exclusively  for  locomotive  boilers,  a  greater  number  of  tubes  can  be 
got  into  less  space,  the  water  being  honey-combed  as  it  were  with 
a  large  amount  of  heating  surface.  The  tubes  for  locomotive  boilers 
are  generally  made  of  composition  metal ;  this  is  absolutely  required 
where  deposits  form  from  impurities  in  the  water.  When  iron  or 
steel  tubes  are  used,  the  small  water  spaces,  in  some  instances  only 
half  an  inch,  soon  get  choked  up,  and  the  steam  does  not  rise  freely; 
and  as  the  arrangement  will  not  allow  of  much  scraping  and  clean- 


46 


MODERN   STEAM    PRACTICE. 


ing,  were  deposits  forming  to  any  great  extent,  it  would  soon  prove 
fatal  to  the  boiler.     To  partially  remedy  this  evil  the  boiler  should 


Fig.  21. — Systems  of  Tubing. 

be  emptied  every  day,  while  for  other  boilers  the  water  must  be 
blown  off  frequently.  With  the  triangular  system  of  tubing  the 
steam  generated  from  the  bottom  row  of  tubes  must  take  many  a 
zigzag  course  before  reaching  the  top,  or  the 
steam  space.  To  obviate  the  difficulties  at- 
tending the  triangular  system  the  square  plan 
is  adopted,  more  especially  for  marine  boilers, 
so  that  when  iron  or  steel  tubes  are  used  there 
is  some  possibility  of  scraping  and  cleaning 
them  occasionally;  and  even  where  composi- 
tion tubes  are  adopted  the  square  system  finds 
favour,  as  the  globules  of  steam  generated 
from  the  tubes  pass  up  in  parallel  rows  be- 
tween the  tubes,  instead  of  following  the  zig- 
zag course  as  in  the  triangular  system. 


DRY    STEAM. 


In  order  to  provide  as  dry  steam  as  pos- 
sible, without  using  a  superheater,  there  should 
be  steam-chests  of  ample  capacity  fitted  to 
all  land  boilers,  in  fact  we  may  say  to  every 
class  of  boiler  where  they  can  be  convenient- 
ly applied ;  but  as  the  steam  still  contains 
watery  particles,  a  separator  may  be  fitted  to  the  steam-pipe.  The 
action  of  this  contrivance  is  very  simple,  and  consists  in  abruptly 


BOILERS   FOR   STATIONARY   ENGINES. 


47 


changing  the  flow  or  current  of  the  steam.  To  a  vertical  chamber 
a  right-angled  pipe  is  suspended,  passing  down  into  the  chamber 
a  little  below  the  exit  pipe;  the  steam  flowing  through  the  pipe 
from  the  boiler  impinges  against  the  elbow,  causing  the  moisture 
contained  in  the  steam  to  trickle  down  the  pipe,  thus  the  water  is 
collected  at  the  bottom  of  the  receiver,  and  is  drawn  ofi"  at  pleasure 
with  a  tap;  this  plan  is  very  simple,  and  it  can  be  made  self-acting 
by  means  of  a  float  and  valve.  We  consider  these  separators  for 
drying  the  steam,  or  rather  separating  the  moisture  contained  in  the 
steam,  should  be  fitted  to  all  steam-pipes. 

Taking  Low-pressure  Steam  from  a  High-pressure  Boiler. — Some- 
times it  is  desirable  to  reduce  the  pressure  of  the  steam,  so  as  to  work  a 
low-pressure  engine  from  a  high-pressure  boiler.  There  are  a  variety 
of  plans  for  doing  so ;  we  have  an  equilibrium  valve,  actuated  by  the 
pressure  of  the  steam  acting  on  a  piston  open  to  the  atmosphere, 
and  regulated  by  a  lever  and  spring-balance,  similar  to  the  safety- 
valve  on  the  locomotive  engine  boiler.  The  valve  is  formed  of  five 
rings  cast  .together,  with  four  vertical  arms,  or  ribs,  having  a  boss 
for  securing  the  valve-spindle;  this  annu- 
lar tube  moves  in  a  corresponding  seat, 
cast  together,  with  vertical  pieces  between 
the  openings;  there  is  an  annular  passage 
all  round  the  seat,  with  a  branch  pipe 
communicating  with  the  steam-boiler.  On 
the  lower  part  of  the  valve-chest  a  branch 
pipe  is  cast  in  communication  with  the 
cylinder  of  the  valve-casing  of  the  engine, 
and  on  the  top  of  the  chest  a  short  cylin- 
der and  piston  are  arranged,  the  piston 
being  connected  to  the  valve  by  a  screwed 
rod  and  nuts.  The  combined  circumfer- 
ential openings  in  the  valve  are  equal  in  area  to  that  of  the  pipe 
from  the  boiler,  and  the  pipe  for  the  engine  must  be  of  sufficient 
area  according  to  the  usual  rules  for  steam-pipes.  By  this  contriv- 
ance the  steam  can  be  regulated  to  the  greatest  nicety.  The  action 
is  as  follows: — After  being  properly  set  with  the  nuts  on  the  valve- 
spindle,  and  the  thumb-screw  on  the  balance  at  the  end  of  the  lever, 
should  there  be  an  accumulation  of  steam  in  the  chest,  after  passing 
the  valve,  the  steam  acts  on  the  piston  in  connection  with  the  valve, 
and  by  its  pressure  lifts  it  partially,  shutting  the  apertures  until  the 


Tig.  23. — Steam -reducing  Valve. 
A,  Valve.  B,  Piston,  c,  Lever  and 
spring  -  balance.  d,  Branch  from 
boiler.     E,  Branch  to  cylinder. 


48  MODERN   STEAM   PRACTICE. 

balance  is  restored,  thus  keeping  up  constant  low  pressure,  regu- 
lated at  pleasure  by  the  thumb-screw  pressing  down  or  releasing 
the  piston  and  the  valve.  One  of  these  valves  can  be  fitted  to  the 
main  steam-pipe,  or  a  separate  one  for  each  cylinder  when  required. 

THE    DETERIORATION   OF  LAND   BOILERS. 

After  a  time  the  plates  of  all  boilers  deteriorate,  the  iron  becomes 
brittle,  and  although  the  plates  have  a  sound-looking  exterior,  with- 
out the  slightest  symptoms  of  corrosion,  yet  such  a  boiler  should 
not  be  worked  beyond  a  certain  number  of  years,  and  certainly  not 
at  so  high  pressure  as  it  was  originally  designed  for;  in  fact,  the 
steam  pressure  should  decrease  year  by  year,  so  as  to  work  it  with 
any  degree  of  safety.  It  must  be  understood,  however,  that  unless 
a  new  boiler  is  properly  managed,  it  is  quite  as  unsafe  as  a  much 
older  one  well  managed.  To  determine  the  number  of  years  a 
boiler  ought  to  last,  with  fair  treatment,  we  must  have  recourse  to 
experiment.  When  it  is  thought  a  boiler  has  done  enough  duty 
test  it  to  destruction.  Such  experiments  are  very  easily  carried  out, 
and  it  is  the  interest  of  steam  users  to  do  so,  that  correct  data  may 
be  arrived  at  by  a  careful  experimentalist. 

We  place  before  our  readers  the  results  of  a  series  of  experiments, 
testing  two  boilers  to  destruction,  instituted  by  Mr.  Peter  CarmichaeV 
and  which  forms  a  useful  contribution  on  the  subject  of  steam- 
boilers.  The  boilers  were  cylindrical,  with  double  flues,  and  were 
used  at  the  Dens  Works,  Dundee,  for  nineteen  years.  They  were 
precisely  alike,  and  of  the  following  dimensions: — Length,  25  feet; 
diameter,  7  feet;  diameter  of  furnaces  and  end  flues,  2  feet  9  inches; 
diameter  of  back  end  of  flues,  2  feet  6  inches.  The  shell  was  made 
of  y%  inch  "  Glasgow  best  iron;"  the  flues  of  Glasgow  best  scrap  iron, 
^  inch  thick,  the  end  plates  being  yV  inch  in  thickness.  The  boilers 
were  kept  in  work  until  the  beginnmg  of  November,  1869,  when  it 
was  resolved  to  take  one  out,  and  test  it  to  destruction  by  water 
pressure.  In  the  case  of  the  above  boilers  the  pressure  has  never 
been  so  great  as  60  lbs.,  and  as  reported  they  were  not  wasted, 
having  always  been  kept  in  good  repair,  and  have  stood  the  peri- 
odical water  test  of  60  lbs.;  therefore  we  may  presume  they  could 
have  been  worked  for  a  year  or  two  longer.  The  fact  of  the  iron 
getting  hard  and  brittle  after  being  in  use  for  a  length  of  time  had 

*  See  Trans.  Inst.  Engineers  and  Shipbuilders  in  Scotland,  vol.  xiiL 


BOILERS   FOR   STATIONARY   ENGINES.  49 

been  often  pointed  out,  and  in  consequence  the  pressure  ought  to 
be  lowered,  or  new  boilers  introduced,  after  they  have  been  working 
for  sixteen  or  seventeen  years.  Before  testing,  all  the  brick  flues 
were  taken  down,  so  that  easy  access  could  be  got  to  all  parts  of 
the  boiler,  but  it  was  left  sitting  on  its  natural  seat.  The  boilers 
were  filled  with  water  of  about  120°  temperature,  and  a  force-pump 
was  then  attached.  To  check  off  the  pressure  no  fewer  than  five 
pressure-gauges  were  used,  four  of  which  nearly  indicated  the  same 
pressure  and  tallied  with  the  safety  valves.  At  80  lbs.  pressure  per 
square  inch  an  examination  was  made,  and  all  appeared  to  be  right; 
but  as  soon  as  the  pump  was  started  again  the  joint  of  the  safety 
valve  was  blown  out,  and  this  stopped  proceedings  for  a  time. 
After  this  joint  had  been  made  good  the  pressure  was  again  brought 
up,  and  at  85  lbs.  the  joint  of  the  feed-pump  pipe,  at  the  front  end 
of  the  boiler,  began  to  leak,  owing  to  the  bulging  out  of  the  end. 
At  100  lbs.  a  number  of  the  longitudinal  seams  of  the  shell  began 
to  exude  water  badly.  The  pressure  was  then  removed,  and  the 
ends  gauged  above  and  below  the  flues,  and  on  the  pressure  being 
again  put  on  the  following  was  the  result: — Front  end  below  flues 
bulged  out  in  centre  y\  inch  at  35  lbs.  pressure;  ^  inch  at  lOO  lbs. 
pressure;  front  end  above  flues  bulged  out  in  centre  ^-^  inch  at 
35  lbs.  pressure,  -^  inch  at  TOO  lbs.  pressure;  back  end  below  flues 
bulged  out  at  centre  -^-^  inch  at  35  lbs.  pressure,  -^  inch  at  lOO  lbs. 
pressure.  The  pressure  was  then  brought  up  to  105  lbs.,  when  the 
ring  seam  at  the  back  of  the  taper  of  the  left-hand  flue  began  to 
crack,  and  the  pump  became  unable  to  keep  up  the  pressure,  owing 
to  the  great  leakage.  This  joint  or  seam  when  gauged,  before 
testing,  measured  2  feet  3^  inches  horizontally,  by  2  feet  5  inches 
vertically;  and  it  gave  way  by  crushing  inwards  on  the  flat  or  hori- 
zontal side,  and  remained  flattened  after  the  pressure  was  taken 
off.  This  boiler  was  then  removed,  and  sent  to  the  foundry  for 
breaking  up. 

Mr.  Carmichael  proceeded  to  clear  away  the  brick  flues  from 
the  sister  boiler.  On  the  15th  December,  1869,  it  was  tested  in  the 
same  way,  having  been  in  use  for  rather  more  than  nineteen  years. 
The  flues  were  gauged,  and  were  found,  with  one  exception,  similar 
to  the  other  boiler.  The  exceptional  one  being  lyi  inch  oval,  it 
was  attempted  to  support  this  flat  part  by  fixing  a  batten  in  the 
line  of  the  shortest  axis  of  the  ellipse,  but  this  was  not  found  to 
be  of  any  use,  as  the  plate  bulged,  oozed  out  below  at  one  end  of 


50  MODERN    STEAM    PRACTICE. 

the  batten  and  above  at  the  other  end,  and  loosened  it  when  the 
strain  came  on.  The  pressure  was  noted  as  before;  at  60  lbs.  pres- 
sure the  feed-pipe  began  to  leak,  the  end  bulging  out  -^  inch.  At 
80  lbs.  the  feed  valve  joint  leaked  very  much,  and  the  longitudinal 
seams  of  the  shell  began  to  exude  water;  at  90  lbs.  the  south  or  right- 
hand  flue  began  to  crack,  as  if  giving  way;  at  95  lbs.  one  of  the  joints 
of  the  shell,  and  the  first  rings  on  the  crown  of  the  boiler,  commenced 
to  spout  water,  and  the  pressure  could  not  be  kept  up,  the  leakage 
being  equal  to  the  supply  of  the  force-pump.  The  joints  of  the  feed- 
valve  were  then  tightened,  and  also  some  parts  of  the  shell  caulked, 
the  right-hand  flue  being  found  to  be  very  much  flattened.  The 
pressure  was  again  put  on,  but  it  could  not  be  got  higher  than 
80  lbs.,  as  the  flues  had  given  way  so  much  as  to  allow  the  water  to 
escape  by  the  fracture  as  fast  as  it  was  pumped  in ;  so  that  the 
highest  pressure  attained  was  95  lbs.,  and  this  pressure  had  so  injured 
the  joints  and  flattened  the  flues  as  to  render  further  experiment 
impossible.  According  to  Fairbairn's  rules  the  bursting  pressure  of 
these  boilers  was  about  300  lbs.  on  the  square  inch,  yet  they  failed 
with  one-third  of  this  pressure.  When  the  boilers  were  broken  up 
the  plates  were  very  brittle ;  indeed,  so  much  so  that  it  was  a  diffi- 
cult matter  to  get  strips  for  testing.  The  rivets  had  likewise  deteri- 
orated, and  the  heads  flew  off"  when  the  plates  were  struck  with  a 
hammer.  The  test  strips  gave  the  following  results: — Shell  in  the 
direction  of  the  fibre,  197  tons;  across  the  fibre,  I9"2  tons;  while 
Glasgow  best  plates  is  24*04  tons  in  the  direction  of  the  fibre,  and 
2r8  tons  across  the  fibre.  Furnace  plates,  direction  of  fibre,  lyi 
tons;  ditto  across,  15 '3  tons.  It  will  thus  be  seen  that  the  mean  of 
the  shell  plates  is  19-45  tons,  and  that  of  the  furnace  i6-2  tons. 
Thus  the  furnace  plates  had  deteriorated  or  weakened  from  227 
tons  to  i6'2  tons,  while  the  shell  had  weakened  from  22*92  tons  to 
19*45  tons.  Now  this  is  after  the  boilers  had  done  duty  for  nineteen 
years;  so  we  are  of  opinion  that  sixteen  years  is  quite  long  enough 
for  boilers  similarly  constructed  to  be  in  use:  and  we  trust  other 
firms  will  follow  Mr.  Carmichael,  so  that  this  all-important  question 
of  the  deterioration  of  boiler  plates  that  have  not  shown  the  slightest 
symptom  of  corrosion,  as  in  these  boilers,  may  be  finally  deter- 
mined, with  diff*erent  qualities  of  plates. 

In  recording  the  testing  of  another  old  steam  boiler,  Mr.  Car- 
michael states,^  "  The  result  of  the  test  so  nearly  coincides  with  that 

*  See  Trans.  Inst.  0/  Engineers  and  Shipbuilders  in  Scotland,  vol.  xxii. 


BOILERS   FOR   MARINE   PURPOSES. 


51 


of  the  two  former  boilers — namely,  95,  105,  and  112  lbs.  pressure, 
that  it  may  be  accepted  as  the  ultimate  strain  that  boilers  of  this 
construction  can  bear  after  being  twenty  years  in  use.  It  is  much 
less  than  that  due  to  the  formula  usually  given  for  a  new  boiler." 

This  boiler  was  twenty-five  years  old.  Some  of  the  plates  and 
rivets  showed  little  or  no  change,  but  brittleness  appeared  in  the 
angle-iron. 


BOILERS    FOR    MARINE    PURPOSES. 


It  is  not  our  intention  to  treat  upon  the  old  flue-boiler,  with  its 
multitudinous  arrangements,  as  that  class  has  now  become  nearly 
obsolete,  though  there  is  still  a  demand  for  them  in  particular  cases, 
such  as  for  dredgers.  The  arrangement  of  this  type  of  boiler 
should  be  as  simple  as  possible,  and  all  the  flues  ought  to  run  in 
the  same  direction,  and  be  of  uniform  width,  commencing  at  the 
part  where  the  flame  and  gases  meet  from  the  furnace.      When 


Fig.  25. 
A  A,  Furnaces. 
B,  Combustion  chamber. 

Fig.  24. 
A  A,  Furnaces. 
B,  Flue. 

C,  Tubes. 

D,  Smoke-box. 

C,  Uptake. 

E,  Uptake. 

r 


Fig.  24. — Flue  Boiler  for  Dredger.  Fig.  25.— Tubular  Boiler  for  Dredger. 

Longitudinal  and  Horizontal  Sections. 

more  than  one  furnace  is  adopted  all  flues  from  the  furnaces  which 
join  into  one  large  flue  should  taper  from  the  furnace  farthest  from 
the  large  main  flue.  This  is  obvious,  as  the  flame  and  gases  from 
that  furnace  mix  with  the  next,  and  so  on ;  care  ought  to  be  taken 


52 


MODERN   STEAM    PRACTICE. 


that  the  main  flue  is  large  enough,  and  that  the  flame  and  heated 
gases  do  not  meet  in  opposite  directions.  As  dredgers  generally 
work  in  harbours,  where  the  water  is  very  muddy,  the  mud  being 
stirred  up  from  the  bottom  by  the  action  of  the  buckets,  small 
tubular  boilers  should  be  avoided;  the  tubes  should  be  at  least 
8  inches  in  diameter,  with  ample  water  space  between  them.  The 
tubes  in  such  cases  are  joined  to  the  tube-plates,  with  a  flange  of 
angle-iron  rivetted  to  the  tube.  In  this  example  there  are  two  fur- 
naces, one  at  each  side  of  the  boiler  meeting  in  a  back  flue,  with 
return  tubes  at  the  same  level  as  the  furnaces.  By  this  means  ample 
water  above  the  tubes,  and  a  large  steam  space,  are  obtained.  As 
it  is  an  object  to  keep  the  weights  low  down,  and  as  dredging 
vessels  are  generally  shallow,  a  low  boiler  should  be  adopted,  placed 
well  below  the  deck,  to  give  free  passage  fore  and  aft  for  the  moor- 
ing chains,  &c. 

For  ocean  steam  ships  the  multitubular  boiler  is  decidedly  the 
best,  although  some  very  good  examples  of  flat  flue  overhead  arrange- 
ments find  favour.  The  tubes  vary  from  2^  inches  to  4  inches  in 
diameter;  and  in  the  merchant  service  they  are  placed  over  the 
furnaces  on  the  return  principle.     When  for  moderate  power,  and 


E 

/ 

D 

c 

^^ 

= — —rr. 

-— — =^^      1^ 

^^^^ 

Longitudinal  Section.  Front  Elevation  and  Transverse  Section. 

Fig.  26. — Ordinary  Tubular  Boiler. 
A  A,  Furnace,     b,  Combustion  chamber,     c,  Tubes.     D,  Smoke-box.     E,  Uptake, 

arranged  fore  and  aft,  the  boiler  is  generally  made  in  one  piece. 
Some  of  these  boilers  have  no  bottoms,  but  are  simply  fitted  with 
a  dry  plate;  while  others,  made  in  the  usual  manner,  have  dry  plates 
laid  on  the  bottom  of  the  furnaces,  thus  preserving  the  rivet  heads 


BOILERS   FOR   MARINE   PURPOSES. 


53 


from  getting  rubbed  away  by  the  mere  friction  of  the  tools  for 
raking  out  the  ashes. 

Some  boilers  are  constructed,  as  it  were,  back  to  back,  in  one 
large  boiler.  By  this  means  two  ends  are  saved,  but  the  great 
weight  of  the  mass  deters  many  from  adopting  this  plan;  but  where 
large  power  is  required  in  small  space,  the  arrangement  has  certain 
advantages.  The  stoke  holes  must  be  "fore  and  aft;"  and  in  general 
the  fore  part  of  the  boiler  is  the  best  steam  producer,  owing  to  the 


Fig.  27. — Double  Boilers.     Longitudinal  Section  and  Front  Elevation. 
A  A,  Furnaces.     B  B,  Combustion  chambers,     c  c,  Tubes.     D  D,  Smoke-boxes.     E  E,  Uptakes. 

air  getting  better  circulated  in  the  stoke  hole,  but,  with  suitable 
air  funnels  from  the  deck,  the  aft  furnaces  of  the  boiler  can  be  pro- 
vided with  the  plentiful  supply  of  air  so  necessary  for  combustion, 
and  for  keeping  the  stoke  hole  cool.  Tljere  is  a  passage  left  be- 
tween the  two  boilers,  forming  a  communication  between  the  fore 
and  aft  stoking-rooms ;  two  funnels  are  fitted,  and  the  general 
arrangement  is  best  suited  for  paddle-wheel  ships. 

Another  modification  differs  materially  from  the  former  example, 
having  one  combustion  chamber  common  to  both  sets  of  furnaces. 
This  will  tend,  in  a  great  measure,  to  efi"ect  complete  combustion, 
and  the  prevention  of  smoke;  that  is  to  say,  if  the  furnaces  are 
properly  constructed  and  fired — the  fore  and  aft  furnaces  being 
fired  alternately,  so  that  one  fire  is  bright  while  the  other  is  receiv- 
ing fresh  fuel.  To  assist  combustion,  air  is  admitted  through  the 
bridge,  thus  getting  partially  heated  before  mixing  with  the  flame 
in  the  combustion  chamber.  These  boilers  are  made  high  to  insure 
ample  steam  room,  while  the  large  area  of  the  uptakes  inside  of 
the  boiler  dries  the  steam.     Indeed,  some  think  this  is  by  far  the 


■54 


MODERN   STEAM   PRACTICE. 


best  plan  for  superheating  the  steam;  far  before  the  complicated 
arrangements  of  separate  superheating  boxes,  with  the  extra  stop- 
valves,  &c.  In  fact,  dry  superheaters  soon  get  out  of  order,  more 
especially  when  there  is  no  steam  in  the  boilers,  as  must  be  the  case 


Longitudinal  Section.  Front  Elevation  and  Transverse  Section. 

Fig.  28. — High  Double  Boiler. 
A  A,  Furnaces.     B,  Combustion  chamber,     c  c.  Tubes.     D  D,  Smoke-boxes.     E  E,  Uptakes. 

for  a  considerable  time  when  the  fires  are  first  kindled.  Any  one 
can  fancy  the  flame  acting  on  a  thin  tube,  roasting,  as  it  were,  the 
steam,  which  subsequently  dries  up  the  lubricants,  and  soon  plays 
havoc  with  the  slide-valves,  pistons,  and  cylinder  faces  of  the  engine. 
Steam  is  only  partially  dried  in  the  best  modern  practice,  and  can 
be  done  in  the  boiler  itself  It  will  be  understood,  in  the  boiler 
described,  that  two  ends  and  two  furnace  backs  are  saved,  the 
material  being  better  disposed  in  the  uptakes. 

As  we  are  dealing  at  present  with  low-pressure  steam-boilers 
suited  for  the  merchant  service,  we  will  draw  attention  to  overhead 
flue  arrangements.  All  boilers  of  this  class  should  be  so  designed 
that  every  part  is  easily  accessible  for  repairs;  and,  when  properly 
constructed,  we  do  not  see  why  the  flues  should  not  last  as  long  as 
any  other  part,  and  certainly  boilers  can  be  designed  so  that  the 
flame  and  heated  gases  will  pass  up  and  down  over  a  greater  length 
of  surface  than  in  the  plain  tubular  boilers.  The  flues  in  this  ex- 
ample are  the  entire  width  of  the  boiler,  leaving  6  inches  of  water 
space  at  the  sides ;  the  flame  passes  to  the  top  of  the  combustion 
chamber  at  the  back  of  furnaces,  then  dips  downwards,  and  so  on, 


BOILERS   FOR   MARINE   PURPOSES. 


55 


the  flues  being  divided  with  suitable  water  spaces,  and  are  strength- 
ened at  the  top  and  bottom  with  conical  tube  stays,  through  which 
the  steam  rises  and  the  circulation  is  effected.  The  water  in  the 
boiler  is  thus  freely  circulated,  with  the  advantage  of  having  a  mode- 


Fig.  29.  — Overhead  Kliie  Boilers.     Longitudinal  and  Transverse  Sections. 
A  A,  Furnaces.     B,  Combustion  chamber,     c,  Flues.     D  D,  Circulating  tubes.     E,  Uptake. 

rate  body  of  water,  which,  under  certain  circumstances,  conduces  to 
rapid  evaporation.  There  are  side  doors  at  the  bottoms  of  the  flues 
for  the  convenience  of  cleaning  them  out,  which  can  be  done  in 
some  instances  while  the  vessel  is  under  way.     Another  form  of  flue 


f'g-  30.— Overhead  Fkie  Boilers.     Longitudinal  and  Transverse  Sections. 
A  A,  Furnaces.     B,  Combustion  chamber,     c.  Flues,     d.  Smoke-box.     E,  Uptake. 

boiler  in  extensive  use  materially  differs  from  the  foregoing  example. 
The  flues  are  quite  narrow,  and  are  arranged  overhead,  similar  to 
tubular  arrangements.     The  flues  are  3  feet  9  inches  deep,  6  feet  in 


56 


MODERN    STEAM    PRACTICE. 


length,  with  2  inches  of  space  for  thfe  flame  to  pass  through,  and  the 
pitch  of  the  flues  is  4^  inches.  They  are  formed  of  two  parallel 
plates  for  the  sides,  with  U-shaped  pieces  at  the  top  and  bottom; 
the  side  plates  are  flanged  at  the  ends,  as  well  as  are  the  U-pieces  at 
the  top  and  bottom,  for  uniting  them  to  the  tube  plates.  The  method 
of  rivetting  the  top,  bottom,  and  the  sides  together  is  as  follows:  the 
rivets  are  put  through  the  holes,  then  wedging  bars  are  placed  in 
at  the  top  and  the  bottom,  and  means  taken  to  secure  them  in  their 
places.  Thus  the  rivets  are  firmly  held  in  position,  and  are  clenched 
quite  cold;  and  when  each  section  of  the  tubes  are  rivetted  together 
they  are  placed  between  the  tube  plates,  and  firmly  rivetted  thereto. 
This  kind  of  work  requires  to  be  carefully  executed;  for,  should 
great  leakage  occur  at  sea,  the  tubes  are  not  easily  repaired.  The 
flues  are  well  stayed  every  9  inches  apart  either  way;  these  stays 
also  act,  to  some  extent,  as  heat  conductors.  When  the  work  in 
this  class  of  boiler  is  well  executed  it  gives  very  little  trouble  at  sea, 
which  is  essential  in  all  marine  steam  generators. 

The  arrangement  of  low-pressure  boilers  for  ships  of  war  differs 


A  A,  Furnaces. 

B,  Combustion  chamber. 

cc,  Tubes. 

D,  Smoke-box. 

E,  Uptake. 

F,  Chiiniiey. 


E 

\ 

D 

J 

c              1 

ri 

B     \ 

A 

F==^ 

Fig.  31.— High  Boilers,  as  arranged  for  the  Royal  Navy.     Longitudinal  and  Transverse  Sections. 


from  the  tubular  class  adapted  for  the  merchant  service.      There 
are  two  classes,  namely,  high  and  low,  the  former  having  the  tubes 


BOILERS   FOR   MARINE   PURPOSES. 


57 


over  the  furnaces  on  the  return  principle,  while  the  latter  have 
generally  the  furnaces  fore  and  aft,  with  the  tubes  athwart  ship, 
the  tubes  reaching  no  higher  than  the  tops  of  the  furnaces.  The 
best  arrangement  for  the  high  class  are  furnaces  athwart  ship,  with 
the  stoke-hole  between  the  boilers  on  the  centre  line  of  the  vessel — 
the  distance  apart  from  front  to  front  of  the  boilers  being  lO  feet; 
this  is  considered  ample  room  for  the  firemen.  As  the  top  of  the 
boilers  requires  to  be  at  least  i  foot  below  the  water  line,  the  ordinary 
steam-chest  is  dispensed  with,  sufficient  height  being  left  between 
the  top  and  the  water  in  the  boiler.  To  give  free  circulation  fore 
and  aft,  the  uptake  or  dry  smoke  pipe  is  shaped  thus,  A,  flat  at 
the  bottom  sides,  but  rounded  at  the  top,  to  take  the  main  funnel. 
This  is  a  very  good  plan. 

We  have  also  seen  many  arrangements  formed  with  the  steam- 
chest  over  the  firemen's  heads;  a  plan  that  should  never  be  attempted, 
as  such  require  an  artificial  blast  to  keep  free  circulation  in  the  stoke- 
hole, the  usual  plan  being  a  fan  driven  by  a  separate  engine;  but 
in  some  classes  of  war  ships,  such  as  "  Monitors,"  even  this  fan  is 
necessary,  the  "free-board"  in  such  ships  being  so  low  that  in  rough 
weather  the  hatches  require  battening  down,  and  then  ventilation 
must  be  kept  up  by  mechanical  appliances. 

The  low  class  boiler  is 
admirably  suited  for  fine 
midship  sections,  firing 
fore  and  aft.  They  are 
placed  closely  together  at 
the  centre  line  of  the  ves- 
sel, leaving  only  a  space 
of  2  inches  between  the 
lagging,  or  the  wood  cover- 
ing which  is  placed  over 
the  boilers  to  prevent  ra- 
diation. The  furnaces,  say 
three  in  number,  join  in 
one  "athwart -ship  flue," 
widening  from  the  furnace 
at  the  centre  of  the  vessel 
to  those  at  the  sides,  and 
then  passing  into  the  combustion  chamber,  which  runs  fore  and  aft, 
this  chamber  tapering  from  the  furnaces  to  the  extreme  end.     This 


A  ^ . 

1    I  ^ 

zzzzr-         I 


Fig.  32. — Low  Boilers,  as  arranged  for  the  Royal  Navy.  Lon- 
gitudinal and  Horizontal  Sections.  A  A,  Furnaces.  B,  Com- 
bustion chamber,     c,  Tubes.     D,  Smoke-box.     E,  Uptake. 


58 


MODERN   STEAM   PRACTICE. 


is  necessary,  as  the  flame  has  always  a  natural  tendency  to  take  the 
nearest  cut  to  the  funnel:  thus,  when  the  combustion  chamber  is 
made  wide  at  the  furnaces  and  narrow  at  the  extreme  end  the  flame 
and  gases  are  more  equally  distributed  through  the  tubes.  The  tube 
plates  are  placed  at  an  angle,-  for  the  convenience  of  getting  out 
the  tubes  for  repairs;  and  at  the  back,  under  the  funnel,  there  is 
space  left  for  cleaning  out  the  tubes. 

When   the  boiler  space   is  rather   limited,   as   in  narrow  vessels 

such  as  despatch  boats,  the  fur- 


naces are  arranged  fore  and  aft, 
with  two  furnaces  at  the  centre 
of  the  ship,  with  separate  com- 
bustion chambers  for  each  fur- 
nace. This  arrangement  will 
suit  best  when  the  stoke-hole 
is  forward,  so  that  a  current  of 
air  freely  passes  through,  the 
air  supply  being  greatly  im- 
proved by  the  forward  motion 
of  the  ship.  The  tubes  are 
arranged  at  the  sides  on  the 
return  principle,  but  they  are 
placed  no  higher  than  on  a  level 
with  the  top  of  the  furnaces. 


Fig.  33. — Low  Boiler  for  Despatch  Boats.  Transverse 
and  Horizontal  Sections,  a  a.  Furnaces,  b  b.  Combus- 
tion chambers,  cc,  Tubes.  DD,  Smoke-boxes,  e,  Uptake. 


The  high  and  low  pressure  combined  engines  necessitate  a  stronger 
form  of  steam-generator,  for  which  circular  boilers  are  decidedly  the 
strongest.  One  arrangement  of  double  boiler  has  three  furnaces 
at  each  end,  the  middle  one  being  placed  much  lower  than  the  two 
side  ones;  this  is  done  to  fill  up  the  dead  water  space  at  the  bottom. 
The  furnaces  are  fore  and  aft,  with  one  combustion  chamber  com- 
mon to  both  ;  they  are  provided  with  dry  uptakes  fitted  to  the  fronts. 
When  four  uptakes  are  arranged  for  one  funnel,  each  boiler  has  a 
separate  tubular  uptake  with  a  flue  running  through  it.  All  the 
uptakes  converge  to  the  centre  of  the  vessel ;  these  uptakes  serve 
the  purpose  of  superheaters,  and  the  inner  tube,  or  flue,  is  strength- 
ened with  rings  of  angle-iron.  For  300  horse-power  nominal,  the 
boilers  being  1 3  feet  6  inches  in  diameter,  the  heating  surface  in  each 
is  as  follows:  2  3o8"88  square  feet  in  tubes,  100  square  feet  in  fire- 
box, 248'22  square  feet  in  furnaces,  making  a  total  for  two  double 
boilers,  $3^4'^  square  feet,  or  17 71  square  feet  per  nominal  hori:,e- 


BOILERS   FOR   MARINE   PURPOSES. 


59 


power.     So  it  will  be  seen  that  circular  arrangements  can  be  placed 
in  almost  as  little  space  as  ordinary  marine  boilers. 


Fig-  3^- — High-pressure  Double  Boilers.     Transverse  and  Longituamai  bci-Lnjiis. 
A  A,  Furnaces,    b.  Combustion  chamber,  c  c,  Tubes.    D  D,  Smoke-boxes,    e  e,  Uptakes.    F,  Separate  uptake. 

Some  are  arranged  for  only  two  furnaces  in  each  single  boiler, 
with  tubes  overhead  as  in  the  previous  example,  and  having  one 
combustion  chamber  common  to  both  furnaces;  this  chamber  at 


Fig.  35- — High-pressure  Boilers.     Transverse  and  Longiuidinal  Sections. 
AA,  Furnaces.     B,  Combustion  chamber,     c.  Tubes.     D,  Smoke-box.     E,  Separate  uptake. 

the  back  of  the  furnaces  is  made  large;  indeed,  in  all  boilers  hav- 
ing tubes  on  the  return  principle  the  combustion  chambers  should 


6o 


MODERN   STEAM    PRACTICE. 


have  ample  capacity,  so  that  the  flame  hangs,  as  it  were,  before 
passing  through  the  small  tubes,  giving  more  time  to  abstract  the 
heat  from  the  gases  before  they  pass  up  the  chimney.  This  is  more 
required  when  the  uptakes  in  front  of  the  furnaces  are  made  dry, 
or  separate  from  the  body  of  the  boiler,  so  as  to  keep  the  stoking- 
room  as  cool  as  possible.  For  moderate  power,  say  300  horse- 
power nominal,  four  boilers  are  adopted,  with  uptakes  arranged 
for  two  funnels;  and  should  the  section  of  the  vessel  be  very  fine, 
with  a  great  rise  of  floor,  the  back  end  can  be  bevelled  or  cut  away 
at  the  bottom  to  suit  the  form  of  the  ship.  All  the  flat  parts  are 
stayed  in  the  usual  manner.  For  ships  of  war,  when  the  stoke- 
hole is  fore  and  aft,  on  the  centre  line  of  the  vessel,  the  uptakes 
should  form  part  of  the  boiler,  as  dry  uptakes  would  make  it  intoler- 


Fig.  36. — High-pressure  Boilers,  as  arranged  for  the  Royal  Navy. 
A  A,  Furnaces,     b,  Combustion  chamber,    cc,  Tubes.    D,  Smoke-box.    e  E,  Separate  uptakes.    F,  Chimney. 


ably  warm  for  the  firemen.  The  uptakes,  or  "  lumleg,"  should  be 
made  double ;  they  can  be  made  slightly  oval,  and  be  strengthened 
with  conical  tubes,  so  that  the  steam  freely  passes  through  them ; 
and  when  great  steam  pressure  is  demanded  the  insides  and  the 
outsides  of  the  uptakes  should  be  well  secured  with  screwed  stays; 
this  arrangement  will  make  a  very  effective  superheater.  The  top 
of  the  uptakes  must  be  below  the  water  line.  When  one  funnel  is 
required  for  six  boilers,  it  is  placed  centrally  between  the  four  front 
boilers,  and  the  aft  boilers  have  dry.  pipes,  thus  joining  the  three 
boilers  on  a  side;  the  back  of  the  boilers  at  the  bottom  are  cut 
away  to  suit  the  form  of  the  ship,  but  when  this  is  not  required 
they  should  be  straight,  thus  simplifying  the  construction.  The  up- 
takes must  be  fitted  with  the  usual  outer  casings,  for  taking  away 
the  vitiated  atmosphere  from  the  stoking-rooms. 


BOILERS   FOR   MARINE   PURPOSES. 


6i 


For  small  power  for  great  steam  pressure,  one  furnace  is  fitted 
with  return  tubes  at  the  side;  while  other  boilers  have  the  furnace 
central  with  the  boiler,  with  return  tubes  overhead  and  at  each  side. 
The  lower  tubes  in  such  an  arrangement  should  be  larger;  thus  the 
flame  is  drawn  down,  as  it  were,  and  the  bottom  tubes  by  this  plan 
are  kept  free  from  soot  deposit.  Another  arrangement  has  two 
furnaces  in  each  boiler,  with  the  combustion  chamber  at  the  back 
of  the  furnaces,  and  then  the  tubes  placed  direct  through  the  boiler, 
thus  entailing  a  long  boiler;  and  this  plan  is  good  when  there  is 


err: 

• 

D 

^— 

B     i 

\ 

A 

E 

• 

r~" 

"" 

f- 

B 

=_ ^=1 

/ 

A               ^ 

C 

_. 

[j 

Figs.  37,  38,  39. — Small  High-pressure  Boilers. 
A,  Furnace.     B,  Combustion  chamber,     c.  Tubes.     D,  Dry  uptake.     E,  Steam  dome. 

sufficient  room  in  the  vessel.  When  a  steam-chest  can  be  fitted, 
it  is  preferable  to  do  so;  and  it  is  found  a  great  advantage  in  such 
small  boilers  to  line  the  combustion  chamber  with  fire-brick.s,  having 
apertures  for  the  smoke  to  freely  pass.  The  steam  pressure  usually 
adopted  is  from  40  to  60  lbs.  per  square  inch,  and  such  boilers  are 
best  suited  for  river  navigation,  where  good  fresh  water  is  obtained. 
As  some  river  boats  are  made  very  shallow,  and  constructed  of 
very  light  scantling,  it  is  desirable  to  have  the  boiler,  and  all  the 
machinery,   designed  to  spread  over  a  large  surface;  and  when 


62  MODERN    STEAM   PRACTICE. 

lOO  lbs.  steam  pressure  is  used,  boilers  of  the  locomotive  type  are 
decidedly  the  best,  and  they  can  be  made  of  steel,  thus  tending 
materially  to  increase  the  carrying  power  for  cargo  by  lightening  the 
boiler.  The  same  class  is  largely  used  for  steam-launches,  having 
the  whole  of  the  machinery  fitted  thereto. 

Torpedo  boats  are  now  fitted  with  the  locomotive  type  of  boiler, 
carrying  a  working  pressure  of  about  120  lbs.  per  square  inch.  The 
draught  is  forced  by  a  fan  blast.  The  evaporation  in  these  boilers 
per  lb.  of  coal  seems  to  be  about  7  lbs.,  and  the  evaporation  per  hour 
per  square  foot  of  heating  surface  varies  from  1 1  to  18  lbs.  The  coal 
consumed  per  hour  per  square  foot  of  grate  varies  from  50  to  lOO  lbs. 

The  haystack  boiler,  originally  introduced  in  Clyde  river  practice, 
is  well  suited  for  vessels  of  light  draft.  The  shell  is  cylindrical 
with  a  dome-shaped  top.  The  tubes  are  placed  vertically,  with  the 
furnaces  beneath  and  around  the  sides. 

PROPORTIONS   FOR    MARINE   BOILERS. 

When  a  number  of  boilers  are  to  be  designed  of  various  sizes,  it 
will  facilitate  the  designer  if  he  fixes  on  the  scale  to  be  universally 
adopted,  and  get  the  drawing-paper  prepared  with  light  lines,  ruled 
in  2-inch  squares,  according  to  the  scale  determined  on,  these  squares 
corresponding  to  the  pitch  of  the  rivets,  or  2  inches  between  centre 
and  centre.  It  is  by  far  the  cheapest  and  best  arrangement  where 
the  front  and  the  sides  are  worked  square  at  the  corners,  the  back 
at  the  top  and  the  bottom  being  rounded,  as  in  many  instances 
this  requires  to  be  done  to  fit  the  midship  sections  of  the  vessel. 
Boilers  so  designed,  and  drawn  on  ruled  paper,  greatly  assist  the 
draughtsman  in  getting  up  the  working  drawings  for  the  work- 
shop. 

After  making  a  rough  sketch  of  a  boiler,  we  know  about  the 
length,  breadth,  and  the  height  required,  and  commencing  on  the 
side  of  a  square,  we  lay  off  the  length,  breadth,  and  the  height  per 
scale;  thus  the  configuration  of  the  boiler  is  represented  by  so  many 
squares ;  the  length,  breadth,  and  the  height  should  always  be  even 
dimensions,  and  there  is  nothing  to  prevent  all  boilers  being  so 
constructed.  We  may  now  set  out  the  plating,  taking  the  centre  of 
the  squares  as  the  edges  of  the  plates,  wherever  we  arrange  the  joints, 
breaking  bond  where  required.  It  is  evident  that  the  plates  must  be 
always  of  even  dimensions.  Each  plate  will  contain  as  many  rivets, 
of  the  universal  pitch  of  2  inches,  as  there  are  squares;  thus  by 


BOILERS   FOR   MARINE   PURPOSES.  63 

counting  the  number  of  squares  in  each  line  of  plating  in  the  length 
and  the  breadth  we  arrive  at  the  true  length  and  breadth  of  each 
plate  without  using  a  scale,  the  ruled  paper  being  the  universal 
scale  for  all  flat  surfaces ;  all  the  other  parts  of  the  boiler  where 
practicable  should  be  set  out  in  like  manner,  and  after  they  are 
marked  on  the  drawing  No.  i,  No.  2,  &c.,  these  are  the  marks 
that  must  be  numbered  on  each  plate  as  delivered  from  the  rolling- 
mills.  No.  I  plate  will  contain  so  many  rivets  in  the  length  and 
breadth,  thus  the  machinemen  need  never  apply  a  foot-rule,  but 
simply  adjust  them  on  the  travelling  table  of  the  drilling  or  punching 
machine,  and  the  machine  itself  will  do  the  work  of  drilling  or 
punching  the  plates  with  mathematical  precision,  the  plates  being 
previously  planed  on  the  edges  to  the  correct  size. 

In  all  Government  contracts  the  top  of  the  boiler  must  be  at 
least  I  foot  below  the  water  line.  To  insure  ample  steam  room 
3  feet  6  inches  is  allowed  from  the  top  of  the  boiler  to  the  top  of 
the  flues.  For  boilers  intended  to  run  out  about  four  times  the 
nominal  horse-power  make  an  allowance  of  "68  to  7  of  a  square 
foot  of  fire-grate  surface,  per  nominal  horse-power,  and  from  18 "8 
to  19  square  feet  of  heating  surface,  taking  the  whole  circumference 
of  the  small  tubes  that  in  multitubular  arrangements  is  available, 
including  the  flues,  sides,  and  the  tops  of  the  furnaces  above  the 
fire-grate,  and  one  half  of  the  back  tube-plate  may  be  included  in 
the  total  heating  surface.  Composition  tubes  are  usually  adopted, 
having  an  external  diameter  of  2^  to  3^  inches,  and  the  pitch  of 
the  tubes  3^  to  4^  inches.  The  length  of  the  tubes  may  vary 
from  5  feet  6  inches  to  7  feet,  but  should  never  exceed  that  length. 

Fire  Grate  and  Heating  Surface  for  Indicated  Horse-power. — For 
ever}^  indicated  horse-power  the  engine  is  intended  to  work  at,  make 
an  allowance  of  about  3  to  3^  square  feet  of  heating  surface,  and 
one-eighth  of  a  square  foot,  or  18  square  inches,  of  fire-grate  for 
every  horse-power  indicated.  The  consumption  of  coal  per  square 
foot  of  grate  is  about  20  lbs.  per  hour,  and  the  water  evaporated 
about  9  lbs.  per  lb.  of  coal. 

Writing  on  this  subject.  Professor  Rankine gives  as  follows: — "The 
greatest  available  heat,  or  the  rate  of  expenditure  of  heat  upon  the 
steam,  is  to  be  compared  in  units  of  work,  by  dividing  the  greatest 
indicated  power  required  in  units  of  work,  per  unit  of  time  (say  in 
foot-pounds  per  hour),  by  the  probable  efficiency  of  the  engine ;  or, 
otherwise,  multiply  the  pressure  equivalent  to  the  rate  of  expendi- 


64  MODERN   STEAM   PRACTICE. 

ture  of  heat  by  the  total  cyhnder  capacity,  and  by  twice  the  number 

of  revolutions  per  minute. 

First  Method. 

Probable  indicated  power, -. 743 

X  foot-pounds  per  hour  (in  indicated  horse-pov/er), 1,980,000 

1,471,140,000 
The  above  divided  by  the  probable  efficiency  of  the  steam,  o'i2,  gives 
the  available  heat  required  in  foot-pounds  per  hour, =12,259,500,000 

Second  Method. 

Estimated  pressure  equivalent  to  rate  of  expenditure  of  heat  in  steam 
(lbs.  on  the  square  inch)  108}^  x  estimated  total  cylinder  capacity  in 
prism  of  I  foot  x  i  inch  x  inch  by  twice  the  number  of  revolutions  per 
hour, 39.033 

4.228,575 
28,992 

12,259,484,650 

*' Available  Heat  required  in  foot-pounds  per  hour. — The  available 
heat  of  combustion  of  i  lb.  of  fuel  (or  rather  coal)  is  to  be  estimated 
by  multiplying  the  total  heat  of  combustion  of  i  lb.  of  fuel  by  the 
efficiency  of  the  furnace. 

"The  total  heat  of  combustion  of  i  lb.  of  coal  of  a  good  quality  for 
marine  purposes  may  be  estimated  at  from  9,000,000  to  10,000,000 
foot-pounds,  and  that  of  the  very  best  at  12,000,000  foot-pounds. 
Inferior  qualities  about  two-thirds  of  the  above  estimates. 

"The  efficiency  of  the  furnaces  may  be  roughly  estimated  as  fol- 
lows— Divide  the  intended  number  of  square  feet  of  heating  surface 
per  lb.  of  fuel  per  hour,  by  the  same  number  -f-  0*5,  eleven-twelfths 
of  the  quotient  will  be  the  probable  efficiency  nearly.  The  following 
are  examples: — 


Square  Feet 

Heating  Surface 

per  Lb.  of  Fuel 

per  Hour. 

Efficiency 

of 
Furnace. 

Available  Heat 

per  Lb.  of  Coal 

of  Total  Heat, 

10,000,000. 

Small  Value  for  Marine  Boilers 

0-50 

0-46 

4,600,000 

r 

075 

0-55 

5,500,000 

i-oo 

061 

6,100,000 

Ordinary  Values  in  Marine  Boilers  - 

1-25 

0  65 

6,500,000 

1-50 

069 

6,900,000 

^ 

2'00 

073 

7,300,000 

Water  Tube  and  Cellular  Boilers,  j 

3-00 

6  00 

079 
0-84 

7,900,000 
8,400,000 

"The  most  common  values  of  the  available  heat  of  a  pound  of  good 


BOILERS   FOR   MARINE   PURPOSES.  6.5 

Steam  coal  in  marine  boilers  are  5,000,000  to  6,000,000  foot-pounds, 
making  an  allowance  of  20  to  50  per  cent,  for  waste,  &c. 

"To  find  the  probable  greatest  rate  of  consumption  of  fuel,  divide 
the  available  heat  per  hour  by  the  available  heat  of  combustion  of 
I  lb.  of  fuel  (example)  available  heat  per  hour,  12,260,000,000 -r- 
available  heat  of  combustion  per  lb.  coal,  say  5,500,000  =  2229  lbs., 
probable  consumption  of  fuel  per  hour. 

"To  find  the  proper  area  of  heating  surface,  multiply  the  rate  of 
consumption  of  fuel  in  pounds  per  hour  by  the  intended  area  of 
heating  surface  to  each  pound  of  fuel  per  hour,  that  is  usually  from 
^  to  13^  square  foot. 

"To  find  the  proper  area  of  fire-grate,  divide  the  rate  of  consump- 
tion of  fuel  in  pounds  per  hour  by  the  weight  of  fuel  in  pounds  to 
be  burned  per  hour  on  each  square  foot  of  grate,  the  quantity  ranges 
in  ordinary  boilers  from  16  to  12  lbs.,  and  the  latter  limit  may  be 
considered  a  suitable  rate  for  the  most  rapid  combustion  at  high 
speed,  provided  air  is  admitted  above  the  fuel  to  burn  its  gaseous 
constituents.  In  some  grates  the  combustion  is  as  low  as  from  6 
to  12  lbs. 

"  The  total  sectional  area  of  flues  (or  tubes)  is  from  one-fifth  to  one- 
seventh  of  that  of  grate,  the  area  of  the  chimney  one-tenth  of  that 
of  the  grate. 

"The  capacity  of  marine  boilers  is  equal  to  the  heating  surface 
multiplied  by  about  i  foot  for  flue  boilers,  or  0"625  of  a  foot  for 
tubular  ones  (exclusive  of  furnace  room),  including  all  internal  parts ; 
the  contents  may  be  estimated  as  nearly  equal  to  the  area  of  fire- 
grate multiplied  by  from  6  to  8  cubic  feet,  one-fifth  being  steam- 
room,  and  the  rest  partly  water  space,  &c." 

The  following  are  some  of  the  relations  which  exist  in  recent 
marine  practice: — 

Grate  Surface  in  square  feet  =  Nominal  Horse-power  x  %. 

Heating  Surface  in  square  feet  =  25  to  28  times  the  Grate  Surface. 

And  |ths  of  the  total  Heating  Surface  =  Tube  Surface. 

r\    r^    4.    a    c       ■                r    ..      Indicated  Horse-power 
Or  Grate  Surface  in  square  feet  = £- ; 

o 

And  Heating  Surface  in  square  feet  =  Indicated  Horse-power  x  3^. 

Staying. — Flat  surfaces,  such  as  for  low-pressure  marine  boilers, 
must  be  strengthened  with  a  suitable  number  of  stays.  The  dis- 
tance between  the  stays  may  be  18  inches  for  pressures  below  20  lbs. 
per  square  inch,  but  for  pressures  above  20  lbs,  per  square  inch,  the 

6 


66  MODERN    STEAM    PRACTICE. 

distance  between  should  be  16  inches,  in  the  parts  that  require 
periodical  inspection,  but  in  confined  places  where  it  is  not  easy  of 
access  14  inches  between  the  stays  may  be  adopted.  As  corrosion 
rapidly  sets  in,  the  stays  must  be  made  of  greater  strength,  in  the 
first  instance,  than  what  is  actually  required ;  and  it  is  advisable 
that  all  the  stays  should  be  rivetted  to  angle-iron  secured  to  the 
boiler,  palms  or  flat  pieces  being  forged  on  the  stays  for  taking  the 
rivets.  By  this  plan  the  angle-iron  materially  stiffens  the  sides  ot 
the  boiler.  When  the  sides  of  the  boiler  are  stayed  with  round  bar- 
iron,  screws  are  formed  at  each  end,  the  diameter  at  the  bottom  of 
the  thread  being  the  same  as  the  main  body  of  the  bar:  thus  the 
ends  being  larger  than  the  bar,  are  more  easily  passed  through 
and  through.  These  stays  have  nuts  on  the  outside  and  inside  of 
the  plates,  with  washers  for  screwing  the  nuts  against:  by  this  means 
the  plates  can  neither  bulge  out  nor  collapse.  The  sides  of  the 
furnaces  and  water  spaces  all  round  the  combustion  chamber  at  the 
back  of  the  boiler  have  screwed  stays  similar  to  a  locomotive  boiler- 
These  stays  are  simply  short  bars  of  iron,  screwed  from  end  to  end, 
the  plates  being  tapped  to  receive  them,  so  that  when  they  are 
screwed  into  the  two  plates,  each  bar  forms  a  secure  stay  to  resist 
bulging  and  collapsing;  and  as  they  require  to  be  at  times  removed 
they  are  not  rivetted  as  in  the  locomotive  boiler,  but  merely  fitted  with 
nuts  on  each  plate.  The  stays  for  the  sides  of  the  furnaces  should 
be  well  kept  out  of  the  fire;  they  can  generally  be  so  arranged  that 
the  top  rows  are  above  the  live  coal,  as  high  up  as  convenient,  and 
the  bottom  rows  entirely  below  the  fire-bars.  The  tube-plates  should 
be  properly  stayed.  Some  makers  prefer  using  tube-stays,  well 
screwed  at  the  ends  and  fitted  with  outside  and  inside  nuts.  Some- 
times collars  are  formed  on  the  stay-tubes  for  the  inside,  and  nuts 
on  the  outside.  This  is  not  a  very  good  plan,  for  should  anything 
happen  to  a  tube,  there  is  a  difficulty  in  taking  it  out,  and  it  is  evident 
that  it  cannot  be  replaced.  The  best  method  of  staying  the  tube- 
plates  together  is  by  sacrificing  some  of  the  tubes  as  heating  surface, 
and  staying  with  plain  round  bars  screwed  at  the  ends,  with  nuts  inside 
and  outside  of  the  plates.  Although  for  the  working  parts  of  marine 
engines,  and  all  parts  subjected  to  tension,  4000  lbs.  per  square  inch 
is  allowed  for  wrought-iron,  it  is  advisable  for  the  stays  only  to 
allow  about  3000  lbs.  per  square  inch.  We  will  now  run  out  the 
number  and  diameter  required  in  a  flat-sided  boiler,  supposing  the 
side  is  10  feet  by  1 1  feet,  and  say  56  stays  can  be  conveniently  got 


BOILERS   FOR   MARINE   PURPOSES.  6/ 

in.  Find  the  number  of  square  inches  in  the  surface,  multiply  by 
the  pressure  per  square  inch,  say  20  lbs.;  thus,  lOX  ii  X  144=15,840 
X  20=316,800  lbs.,  equal  pressure  on  the  whole  surface,  which, 
divided  by  3000,  gives  the  total  area  of  the  stays;  and  again  by  56, 
gives  the  area  in  square  inches  for  each  stay  at  the  bottom  of  the 

thread:  ^- — —=  105 "6-^56=1 '8  square  inch  area  for  each  stay,  say 

13^  inch  in  diameter.  For  the  screwed  stays  in  the  furnace  side- 
plates  the  diameter  is  generally  i  ^  inch,  with  spaces  to  suit;  and  the 
stays  which  secure  the  sides  and  bind  the  top  and  bottom  together — 
z.e.  the  stays  passing  through  the  water  spaces  between  the  small  tubes 
— are  made  of  flat  bar-iron,  with  screwed  ends  and  nuts  inside  and  out 
Fire-bars. — Wrought-iron  fire-bars  have  a  breadth  of  i^  inch 
at  the  top  and  y^,  inch  at  the  bottom,  and  are  3  inches  deep. 

Weight  of  Wrought-iron  Bars, 3  ft.  3  in.  long  =  30  lbs. 

Weight  of  Cast-iron  Bars, 2       o       ,,        =19 


Weight  of 

do. 

Weight  of 

do. 

Weight  of 

do. 

Weight  of 

do. 

2 

6      „ 

=  7-4 

3 

0      ,, 

=  27^5 

3 

6      „ 

=  32-0 

4 

0      „ 

=  365 

Cast-iron  bars  have  a  breadth  of  full  T/^  inch  at  the  top  and  full 
^  inch  at  the  bottom,  the  depth  ranges  from  3  to  4^  inches,  and 
the  distance  between  bars  from  }i  to  j4  inch. 

Tube  Area,  Furnaces,  &c. — The  calorimeter  of  the  boiler  or  sec- 
tional area  of  the  tubes  is  a  subject  no  one  need  trouble  himself 
about,  as  the  combined  area  of  the  tubes  is  greatly  in  excess  of 
what  is  required,  and  in  which  we  have  no  choice,  as  it  depends  on 
the  length  of  the  tubes  that  can  be  introduced.  The  ordinary  size 
of  tubes  for  the  merchant  service  varies  from  3  to  4  inches  external 
diameter,  and  from  6  feet  to  7  feet  in  length;  while  for  the  Royal 
Navy  the  tubes  are  2],^  to  3^  inches  external  diameter,  and  5  feet 
6  inches  to  7  feet  in  length,  consequently  it  will  be  seen  that  the  longer 
the  tubes  are  the  greater  the  heating  surface,  while  the  combined  area 
through  them  may  be  the  same.  The  only  thing  to  be  considered 
is  to  arrange  them  so  as  to  get  the  greatest  effect  from  the  fuel.  For 
the  Royal  Navy  composition  tubes  are  usually  adopted,  as  their  con- 
ductive power  is  greater,  and  'the  water  spaces  are  not  so  liable  to 
choke  up  with  deposit;  but  for  the  mercantile  marine  iron  and  steel 
tubes  are  extensively  used.  The  tubes  in  either  case  are  driven  hard 
into  the  holes  in  the  tube-plates,  and,  after  they  are  all  in  their  places, 
are  widened  out  with  a  suitable  tool,  and  the  edges  neatly  laid  over. 


68  MODERN   STEAM   PRACTICE. 

Sometimes  ferrules  are  fitted  and  driven  into  the  tubes  nearest  the 
furnaces,  but  at  the  smoke-box  end  they  are  simply  expanded,  and  a 
slight  countersink  left  in  the  holes  on  the  outside,  thus  forming  a  collar 
when  the  ends  of  the  tubes  are  laid  over.  The  flues  and  combus- 
tion chamber  at  the  back  of  the  boiler  are  of  great  importance,  more 
especially  with  short  tubes  arranged  and  worked  on  the  return  prin- 
ciple. In  many  boilers  of  this  class  the  flame  and  heated  gases  pass 
too  rapidly  through  the  boiler  into  the  chimney,  and  if  not  fitted  with 
a  high  uptake  causes  great  waste  in  fuel,  the  flame  and  gases  having 
little  time  to  act  on  the  heating  surface.  The  combustion  chamber 
should  be  made  large,  so  as  to  make  the  flame  hang  in  the  flues 
before  passing  through  the  small  tubes.  The  usual  size  at  the  top 
of  the  combustion  chamber  is  i8  inches,  and  at  the  bottom  22  inches, 
from  the  tube-plate  to  the  back  of  the  chamber,  this  being  actually 
required  in  all  cases  to  properly  expand  and  lay  over  the  ends  of 
the  tubes.  It  is  advisable,  however,  not  to  increase  this  space  to  any 
great  extent,  more  especially  for  high  pressure,  as  large  flat  surfaces 
are  not  to  be  desired.  But  for  moderate  pressure,  22  inches  at  the  top 
and  26  inches  at  the  bottom  will  tend  to  retard  the  flame  and  gases  in 
the  combustion  chamber.  The  area  over  the  bridges  is  from  18  to 
19  square  inches  per  nominal  horse-power;  thus  it  will  be  seen  that 
the  calorimeter  of  the  tubes  is  greatly  in  excess  of  this.  It  must  be 
acknowledged  by  all  that  marine  boilers  should  have  as  many  fur- 
naces as  possible,  bearing  in  mind  that  there  is  a  certain  size  of 
furnace  very  convenient  to  manage,  and  other  sizes,  above  or  below, 
that  are  not  so  convenient.  A  good  medium  is  a  width  of  2  feet 
9  inches,  and  certainly  not  less  than  2  feet  6  inches,  or  greater  than 
3  feet  3  inches,  and  from  6  feet  to  7  feet  in  length,  but  should  not 
exceed  the  latter,  as  a  7-feet  furnace  is  quite  long  enough  to  manage 
properly.  But  in  some  instances  the  boiler  room  is  so  limited  that 
length  must  be  substituted  instead  of  breadth.  Some  makers  have 
even  gone  to  the  extreme  as  regards  the  width,  considering  if  they 
make  the  furnace  circular,  a  diameter  of  3  feet  6  inches  could  be 
used  with  impunity;  but  experience  proves  the  contrary,  as  with 
ordinary  sea  water  scale  will  form,  and  accumulating  to  any  great 
thickness,  the  furnace  plates  become  heated  and  the  tops  come 
down,  even  although  there  is  a  plentiful  supply  of  water  in  the  boiler. 
So  as  many  furnaces  of  a  medium  width  as  can  be  conveniently 
arranged  are  far  better  than  a  less  number  of  a  great  width,  con- 
sidering the  more  furnaces  we  have  there  will  be  more  side  surface 


BOILERS   FOR   MARINE   PURPOSES.  69 

exposed  to  the  action  of  the  fire;  for  undoubtedly  at  the  tops  and 
sides  of  the  furnaces  the  water  is  most  rapidly  evaporated,  and 
consequently  a  better  steam-producing  boiler  will  be  obtained, — a 
result  that  all  should  strive  to  reach,  even  although  it  may  be  at 
considerably  more  cost  in  manufacturing. 

Thickjtess  of  Plates  for  Round  Boilers. — As  these  boilers,  for  the 
compound  marine  engine,  are  made  large  in  diameter,  carrying  high 
steam  pressure,  the  best  quality  of  iron  must  be  used,  or  B,  B,  equal 
to  Yorkshire  plates,  the  breaking  strain  being  57,120  lbs.  per  square 
inch;  and  taking  one-fifth  of  the  breaking  strain  of  the  plate  or 
rivetted  seams  as  the  constant  for  this  quality  of  iron,  we  have — 

=  thickness  of  the  shell. 

1 1424 

Thus,  supposing  we  have  a  boiler  142  inches  in  diameter,  and  the 
steam  pressure  70  lbs.  per  square  inch — 


i42j^^  =  .Z7  or  lA  inch  thick. 
1 1424  '        ^ 


1424 

The  seams  should  be  double-rivetted,  which  are  nearly  equal  in 
strength  to  the  solid  plates.  For  the  thickness  of  the  plates  for  the 
other  parts  of  boilers  we  give  two  examples  by  English  and  Scotch 
firms,  the  steam  pressure  being  70  lbs.  per  square  inch  in  each 
case : — 

London  Made.  Leith  Made, 

inches.  inches. 

Diameter  of  Boiler 142         120 

Thickness  of  Shell |-       ^ 

Do.         End  Plate |       |^ 

Do.         Tube  Plate f       f| 

Do.         Furnace  Plate  -^-^      ^ 

Do.         Back  of  Furnace  Plate -jV      iV 

Strength  of  Flue  Tubes  to  resist  crushing.     Example : — 

.43"  inch  thickness  of  plate  x  constant  700000  _ 

7.25  feet  length  of  tube  x  36  inches,  diameter  of  tube  ~ 
ult.  strength  495  ■—  6th  =  82  lbs.  working  pressure. 

In  a  paper  on  the  Strength  of  Boilers,  by  Mr.  J.  Milton,  surveyor 
to  Lloyd's,^  the  question  of  factors  of  safety  is  considered ;  and  it 
is  shown  that  the  ordinary  cylindrical  boiler  is  the  only  really  reli- 
able marine  boiler  at  present  in  use,  and  that  as  the  shell  plates  had 
reached  up  to  a  thickness  of  1 14^  inch,  the  weight  of  such  a  boiler 
became  an  important  item  in  the  load  carried  by  the  ship.     Hence, 

^  See  Trans.  Inst.  Naval  Architects,  session  xviii. 


70  MODERN   STEAM   PRACTICE. 

any  method  whereby  the  boiler  could  be  lightened,  and  yet  kept 
efficient,  would  be  of  great  value  for  mercantile  purposes.  It  is 
shown  that  Prof.  Rankine  and  others  estimate  that  a  factor  of  safety 
of  eight  is  necessary  for  such  a  live  load  as  steam.  The  author 
however,  states,  "  Now  experiments  show  conclusively  that  up  to  a 
temperature  considerably  exceeding  that  at  which  it  is  practicable 
to  use  steam,  wrought-iron  does  not  lose  strength ;  and  as  no  part 
of  a  properly  designed  boiler  is  subjected  to  a  temperature  much 
greater  than  that  of  the  steam  within  it,  without  being  specially 
strengthened,  there  does  not  appear  to  be  any  reason  for  this  great 
difference  of  factor  of  safety.  The  Manchester  Steam  Users'  Asso- 
ciation, founded  by  Fairbairn  for  the  prevention  of  boiler  explosions, 
consider  that  where  boilers  are  well  built  and  carefully  examined 
periodically  a  factor  of  safety  oi  four  is  sufficient,  and  the  correctness 
of  these  views  is  shown  by  the  freedom  from  accidents  in  boilers 
guaranteed  by  them ;  but  of  course  we  are  not  warranted  in  con- 
cluding from  this  that  the  same  factor  would  be  sufficient  for  marine 
boilers,  which  often  cannot  be  subject  to  the  same  careful  and 
systematic  examinations  as  land  boilers.  The  old-fashioned  box 
boiler  working  at  from  lO  to '30  pounds  had  only  a  factor  of  about 
fou7',  and  yet  the  accidents  which  have  happened  with  this  low  factor 
of  safety  were  quite  as  few  in  proportion  to  the  number  of  boilers 
in  use  as  with  the  higher  factor  of  six,  which  is  about  the  present 
practice  of  the  country,  although  at  the  same  time  improved  appli- 
ances have  enabled  boiler-makers  to  make  better  and  more  reliable 
work  than  formerly.  But  although  the  present  factor  of  safety  is 
nominally  six  in  many  boilers  which  are  at  present  at  work,  there 
are  parts  which,  either  from  oversight  or  want  of  knowledge  on  the 
part  of  their  designers,  are  very  much  weaker  than  the  other  parts, 
and  which  considerably  reduce  the  actual  factor  of  safety.  Yet  we. 
find  that  these  specially  weak  parts  are  often  quite  strong  enough 
for  their  work,  for  even  after  many  years'  service  they  do  not  show 
any  signs  of  weakness.  If  these  parts  are  strong  enough,  then  un- 
doubtedly the  extra  strength  of  the  remainder  of  the  boiler  has  been 
so  much  useless  weight." 

On  the  question  of  proportioning  the  strength  of  boiler,  the  effect 
of  expansion  is  pointed  out  as  an  important  agent  in  the  tear  and 
wear  of  a  boilen  "  There  are  certain  strains  which  boilers  are  sub- 
ject to  which  are,  under  certain  conditions,  much  greater  than  any 
which  the  working  pressure  can  bring  upon  them,  and  which  are 


BOILERS   FOR   MARINE   PURPOSES.  7 1 

altogether  independent  of  the  factor  of  safety  employed.  I  mean 
the  strains  brought  upon  the  boiler  by  the  unequal  expansion  of  its 
different  parts.  Ordinary  wrought-iron  plates,  if  left  free  from 
s-tress,  expand  "0000064  of  their  linear  dimensions  for  each  degree 
Falir.  increase  of  temperature.  Also  if  the  plates  are  subjected  to 
stress  they  alter  in  length  a  certain  amount  according  to  the  quality 
of  the  iron;  the  more  ductile  irons  altering  more  for  the  same 
amount  of  stress.  Taking  as  the  mean  value  of  E,  29,000,000  (the 
value  given  by  Rankine)  we  find  that  a  stress  of  186  lbs.  per  square 
inch  will  give  the  same  alteration  in  length  as  1°  Fahr.  If,  now, 
the  ends  of  a  plate  are  rigidly  fixed  so  that  it  is  incapable  of  altering 
its  length,  an  increase  of  i°Fahr.  will  subject  it  to  a  compressive  stress 
of  186  lbs.  per  square  inch,  and  a  decrease  of  1°  to  a  tensile  stress 
of  equal  intensity;  and  it  is  to  be  observed  that  these  stresses  are 
totally  independent  of  the  sectional  area  of  the  plate.  Now,  in  the 
case  of  a  furnace,  the  portion  above  the  fire,  especially  when  coated 
with  even  the  thin  enamel  or  scale  which  is  necessary  to  preserve  it 
from  corrosion,  must  be  considerably  hotter  than  the  portion  below 
the  bars.  Hence  the  top  of  the  furnace  tends  to  get  longer  than 
the  bottom.  If  the  end  fastenings  of  the  furnace  were  so  rigid  as 
to  maintain  the  top  and  bottom  of  same  length,  the  top  would  have 
to  be  compressed  and  the  bottom  stretched,  and  every  difference  of 
a  degree  Fahr.  in  the  temperature  would  produce  a  compressive 
stress  in  top  and  a  tensile  stress  in  bottom  of  93  lbs.  per  square  inch. 
But  actually  the  end  fastenings  are  not  so  rigid,  and  the  strains 
caused  by  the  unequal  expansion  are  not  distributed  from  top  to 
bottom  by  the  ends  only,  but  also  in  a  great  measure  by  the  resist- 
ance to  shear  of  the  plate,  and  hence  the  greatest  stresses  come  at 
the  middle  of  the  length  of  the  furnace.  Also,  it  is  evident  that 
these  strains  are  not  uniformly  distributed,  and  hence  their  maximum 
must  be  greater  than  their  mean,  and  with  a  great  difference  of 
temperature  the  stresses  reach  a  high  figure.  The  only  way  to 
strengthen  furnaces  from  such  strains  is  either  to  prevent  the  differ- 
ence of  temperature,  or  else  to  allow  the  crown  freedom  to  expand." 

The  question  of  reduction  of  strength  of  plates  by  punching  or 
drilling  has  had  much  attention,  and  experiments  go  to  prove  the 
greater  strength  of  drilled  plates.  Steel  plates  should  always  be 
drilled  ;  if  punched,  they  must  be  annealed  afterwards  to  reduce  the 
local  strains  set  up  by  the  action  of  the  punch. 

The  corrosion  of  boilers  is  an  important  matter,  and  recently  since 


72  MODERN    STEAM   PRACTICE, 

the  introduction  of  steel  the  question  has  been  raised  as  to  the  rela- 
tive resistance  of  the  iron  and  steel  plates  to  this  action.  So  far  as 
experiment  or  experience  has  gone,  the  action  seems  to  be  pretty 
much  the  same  in  both  materials.  The  influence  of  scale  upon  the 
steel  plates  is  prejudicial,  as  a  galvanic  action  is  set  up  between  the 
part  covered  with  scale  and  any  parts  not  so  covered,  which  causes 
pitting  of  the  latter.  This  scale  of  black  oxide  can  be  removed  by 
exposure  to  acid,  and  in  ships  building  at  present  for  H.  M.  Navy 
the  plates  are  immersed  in  a  solution  of  sulphuric  acid  and  water  so 
as  to  clear  away  any  scale  which  may  adhere  to  them. 

Where  certain  kinds  of  peaty  water  is  used  for  feeding,  the  boiler 
seems  to  be  quite  unaffected  by  corrosive  action.  This  is  notably 
the  case  in  the  boilers  of  the  Loch  Lomond  steamers,  some  of  which 
after  very  many  years'  service  are  unaffected  by  corrosive  action. 
It  appears  that  a  kind  of  coating,  of  a  dark  or  brownish  colour,  is 
deposited  on  the  iron,  which  protects  it,  and  does  not  appear  to 
affect  the  conducting  power  of  the  plate. 

One  method  of  bringing  about  the  much  to  be  desired  lightening 
of  boilers  is  to  adopt  the  locomotive  type  of  boiler  with  forced  com- 
bustion. This  method  is  now  tried  in  steam  launches,  or  torpedo 
boats,  where  as  much  as  150  lbs.  of  fuel  appears  to  have  been 
burned  per  foot  of  grate  per  hour. 

In  reference  to  this  question  of  economy  of  weight,  The  Engineer, 
in  a  leading  article,  July  8,  1881,  says — "The  modern  high-pressure 
marine  boiler  is  by  no  means  all  that  a  boiler  should  be.  We  may  take 
as  a  type  a  three-furnaced  boiler  to  carry  70  lbs.  Such  a  boiler  will  be 
about  12  feet  in  diameter  by  io-6  feet  long.  It  will  contain  three 
furnaces,  each  three  feet  in  diameter,  and  a  little  more  than  7  feet 
long,  and  each  furnace  will  have  a  separate  back  uptake,  and  sixty 
3-inch  tubes  7  feet  long.  A  boiler  of  this  kind,  if  fitted  with  a  large 
steam  dome,  will  steam  well,  and  may  be  depended  upon,  with  fair 
coal,  to  work  a  pair  of  compound  engines  up  to  500  indicated  horse- 
power. Its  shell  plates  will  be  nearly  i  inch  thick,  and  its  total 
weight  without  water  will  be  roughly  28  tons,  and  it  will  hold  14 
tons  of  water.  Its  gross  weight  therefore  will  be,  under  steam  and 
allowing  for  grate-bars,  &c.,  not  far  short  of  45  tons.  It  will  have 
a  grate  surface  of  about  57  square  feet,  a  tube  surface  of  900  feet, 
the  crowns  of  the  furnaces  will  amount  to  about  lOO  square  feet, 
and  the  uptakes  may  be  taken  as  120  feet  more.  The  total  heating 
surface  will  be  therefore  a  little  over  1 100  square  feet 


BOILERS   FOR   MARINE   PURPOSES,  73 

"If  we  contrast  this  with  a  locomotive  boiler,  we  find  that  the 
latter  will  not  weigh,  complete  with  water  and  in  working  order, 
more  than  12  or  13  tons.  It  will  have  11 00  feet  of  heating  surface, 
and  18  to  20  square  feet  of  grate,  and  it  may  be  depended  upon  to 
develop  600  horse-power  in  a  non-condensing  engine, 

"  The  cubical  space  occupied  by  the  locomotive  boiler  will  not  be 
more  than  one-fourth  of  that  taken  up  by  the  marine  boiler,  and  it 
will  be  on  the  whole  quite  as  economical,  if  not  more  economical." 
In  referring  to  objections  to  the  use  of  the  locomotive  type  of  boiler 
at  sea,  it  is  pointed  out  that  a  fair  trial  has  not  yet  been  made  of 
such  boilers  at  sea  for  mercantile  purposes,  and  that  it  has  proved 
serviceable  in  torpedo  boats. 

Attempts  are  being  made  at  present  to  give  practical  effect  to 
this  question  of  decreased  dead  weight  by  reducing  the  diameter  of 
the  shells,  and  giving  increased  draught  so  as  to  consume  more  fuel 
per  foot  of  grate  surface. 

As  to  the  question  of  the  relative  economy  of  chimney  draught 
and  forced  draught,  it  has  to  be  borne  in  mind  that  although  power 
has  to  be  expended  in  driving  fans  or  blowers  to  produce  a  forced 
draught,  still  in  the  chimney  draught  a  large  proportion  of  the  heat 
of  the  furnace  is  spent  to  produce  and  keep  up  such  draught, 
reaching,  according  to  some  authorities,  to  one-fourth  of  the  avail- 
able heat  of  combustion. 

It  has  been  proposed  to  carry  out  forced  draught  by  jets  of  steam 
in  funnel  or  air  in  ashpit,  or  by  fans  blowing  air  into  ashpit  direct, 
or  into  the  stoke-hole,  the  latter  in  this  case  requiring  to  be  air- 
tight. 

Funnel,  Damper,  &c.  —  The  ordinary  height  of  funnels  for 
steamships  of  the  merchant  service  is  about  32  feet  6  inches 
from  the  top  of  the  steam-chest,  and  about  48  feet  height  from 
the  top  of  the  fire-bars,  the  area  =  |^th  of  fire-grate.  Where 
more  than  one  funnel  is  required  the  arrangement  of  the  boilers 
will  determine  the  number  and  positions  of  the  funnels.  It  is 
very  usual  now  in  large  ocean-going  ships  to  have  two  funnels, 
and  in  some  cases  even  three  funnels,  as  the  City  of  Rome,  Livadia, 
and  other  vessels.  In  the  first-named  ship  the  funnels  are  arranged 
fore-and-aft,  in  the  Livadia  athwart-ships.  The  plates  are  gener- 
ally arranged  in  four  lengths,  the  three  lengths  towards  the  bottom 
9  feet  each,  and  the  top  plates  5  feet  6  inches.  The  joints  are  butted, 
with  strips  inside  of  the  chimney,  and  the  circumferential  joints  are 


74  MODERN   STEAM    PRACTICE. 

made  with  a  flat  ring  and  iron  moulding.  At  the  top  horizontal 
joint,  or  27  feet  from  the  bottom  of  the  funnel,  lugs  are  forged  on 
the  ring,  on  which  to  fix  links  for  the  funnel  shrouds,  which  are 
secured  below  to  the  side  of  the  ship. 

Thickness  of  Bottom  Plates, i\  inch. 

Do.     of  Top  Plates, ^       ,, 

Joint  Straps, 4^  >^  ^     >, 

Flat  Rounded  Moulding, 3  inches. 

The  bottom  of  the  funnel  is  fitted  to  a  cast-iron  ring  secured  to  the 
top  of  the  steam-chest.  Where  four  boilers  are  used  this  ring  is 
divided  into  four  parts,  with  cross  bars  of  cast-iron,  cast  in  one  piece, 
to  which  is  fitted  a  damper  for  each  boiler,  having  an  uptake  from 
each,  independently  of  the  others,  that  the  draught  of  each  boiler 
may  be  regulated  separately.  One  of  the  cross  bars  is  cast  hollow, 
forming  a  pipe  from  the  side  to  the  centre  of  the  ring,  or  centre 
of  the  funnel;  this  is  termed  the  blow-pipe,  and  is  fitted  with  a 
plug-valve  in  connection  with  the  steam-room  in  the  boiler.  The 
engineer  by  this  means  can  urge  on  the  fires  by  blowing  the  steam 
up  the  chimney,  and  thereby  causing  a  partial  displacement  of  the 
air,  which  is  filled  up  by  the  atmospheric  air  rushing  under  the  fire- 
bars and  through  the  holes  left  in  the  furnace  doors,  providing  the 
large  supply  of  oxygen  so  necessary  for  combustion.  With  high- 
pressure  engines  the  waste  steam  from  the  cylinders  is  blown  up 
the  chimney  in  a  manner  similar  to  the  blast-pipe  of  the  locomotive 
engine. 

Funnels  of  large  diameter  are  usually  stayed  internally  with 
round  bar  iron,  to  prevent  them  from  getting  out  of  shape  in  the 
workshop  or  on  carriage  to  the  ship.  For  ships  of  war  the  funnel 
is  made  telescopic,  the  top  part  sliding  into  the  lower  part.  The 
outside  part,  or  lower  portion,  is  formed  conical  at  top,  with  a  cor- 
responding cone  for  the  internal  or  top  portion,  fitted  at  the  bottom. 
Thus,  when  the  top  part  is  hoisted  up,  the  inside  cone  fits  into  the 
outer  one,  and  the  funnel  is  screwed  hard  up  with  set  screws,  swivel- 
ling in  boxes  recessed  in  the  funnel.  The  points  of  the  screws  bear 
on  an  angle-iron,  fitted  round  the  outer  portion.  The  top  part  has 
likewise  the  shrouds  for  securing  the  funnel  to  the  ship's  side.  The 
mechanism  for  hoisting  up  the  funnel  is  a  worm-wheel  and  pinion, 
with  the  necessary  barrels,  chains,  and  guide  blocks.  This  gear 
should,  when  possible,  be  fastened  down  to  the  top  of  the  boilers, 
or  strongly  bolted  to  the  side  plates  of  the  bunkers,  as  the  worm- 


BOILERS   FOR   MARINE   PURPOSES.  75 

wheel  Is  apt  to  jam  in  the  pinion  if  the  frame  for  it  is  not  rigidly- 
secured.  An  outside  air-casing  must  be  carried  up  from  the  top  of 
the  boiler,  or  dry  uptake  if  so  fitted,  to  about  8  feet  above  the  deck, 
for  taking  away  the  vitiated  air  from  the  stoke-hole,  and  protecting 
the  woodwork  of  the  combings  around  the  funnel  from  the  great  heat 
radiated  from  the  uptake.  On  the  deck  there  is  another  casing,  so  as 
effectually  to  keep  the  passage  round  the  funnel  cool.  There  are  holes 
all  round  at  the  tops  of  the  casings,  and  likewise  at  the  bottom,  for 
the  thorough  ventilation  of  the  stoke-hole.  The  waste  steam-pipe  is 
likewise  made  telescopic,  the  bottom  part  having  a  suitable  stuffing- 
box,  through  which  the  top  part  slides  steam  tight,  the  top  part 
having  a  stay,  with  collars  on  the  waste-pipe,  the  stay  being  attached 
to  the  top  or  sliding  part  of  the  main  funnel. 

The  smoke-doors  should  be  hinged  to  flat  bars,  fastened  vertically 
to  the  smoke-box.  The  doors  should  have  an  inside  plate  and  an 
outer  one,  kept  apart  from  the  door  itself,  but  secured  to  it  by- 
ferrules  and  rivets:  the  inner  plate  is  to  protect  the  door  from  the 
fire,  and  the  outer  one  to  keep  the  stoke-hole  cool.  By  this  arrange- 
ment a  current  of  air  passes  freely  between  both  the  inside  and  the 
outside  plates.  There  are  handles,  fitted  with  a  means  of  keeping  the 
door  shut,  so  constructed  that  the  sneck  or  snib  presses  the  door  for- 
cibly against  the  hinge  plates.  The  furnace  doors  are  hinged  so  as 
to  cover  the  apertures  formed  in  the  front  plates,  thus  doing  away  with 
cast-iron  frames,  and  are  pierced  with  air  holes,  having  the  means  of 
regulating  the  supply  of  air  to  the  furnaces.  The  ashpits  are  fitted 
with  dampers  at  front,  hinged  on  a  pin,  having  ratchet  wheels  and 
pawls,  for  regulating  the  supply  of  air  underneath  the  bars,  or,  by 
shutting  them,  damping  the  fires.  The  manhole  on  the  top  of  the 
boiler  should  be  cut  in  the  most  convenient  place,  and  the  door 
secured  on  the  outside  with  a  bridge  piece,  strongly  bolted.  The  size 
of  the  manhole  is  usually  i8  inches  by  14  inches,  which  is  sufficient 
to  allow  a  man  of  ordinary  size  to  pass  through  for  inspecting  and 
cleaning  the  inside  of  the  boiler.  Smaller  doors  are  left  in  the 
front  plate  of  the  boiler,  between  the  furnaces  at  the  top,  of  sufficient 
size  to  allow  a  boy  to  pass  through  for  scaling  the  furnace  tops.  All 
the  necessary  doors  must  be  fitted  at  the  bottom  of  the  boiler,  for 
raking  out  the  sludge,  the  bolts  for  securing  them  being  made  so  as 
to  draw  up  the  door  against  the  inside  of  the  front  plate  of  the  boiler; 
one  large  bolt,  having  a  cross  bar  over  the  hole,  is  by  far  the  best 
plan  for  securing  them. 


y6  MODERN    STEAM    PRACTICE. 

Of  late  years  many  improvements  have  been  made  in  connection 
with  steam  boilers,  with  the  view  of  increasing  the  economy  of  the 
fuel,  and  thereby  rendering  the  boiler  a  more  efficient  steam-gener- 
ator. The  loss  due  to  emission  of  smoke  may  in  many  cases  be 
met  by  careful  firing.  Appliances  known  as  mechanical  stokers 
have  been  introduced,  whereby  the  fuel  is  gradually  fed  to  the  fur- 
nace through  a  hopper  arrangement  in  front,  means  being  adopted 
to  work  the  coal  to  back  of  furnace.  Another  method  of  fuel  feeding 
has  been  recently  tried,  in  which  the  coal  is  charged  upon  a  mov- 
able truck,  which  by  gearing  is  pushed  inside  the  grate  and  below 
the  fire-bars,  the  fresh  coal  is  then  lifted  or  pushed  up  below  the 
burning  fuel,  and  thus  partially  cokes  before  being  consumed. 

Feed-water  heaters  are  also  used,  by  which  it  appears  a  consider- 
able saving  in  fuel  is  effected.  The  covering  of  the  boiler  and 
steam-pipes  has  also  had  much  consideration,  various  non-conduct- 
ing compositions  being  used;  one  of  those  recently  tried  is  slag 
wool  or  silicate  cotton,  partly  made  from  blast-furnace  slag;  it  is 
applied  either  as  a  composition  or  in  slabs  curved  to  suit  the  surface. 

Figs.  39A  and  39B  illustrate  the  most  modern  type  of  marine 
boilers  for  compound  engines,  as  supplied  to  the  S.S.  Parisian,  built 
byR.Napier&  Sons,  Glasgow,  for  the 'Allan  Line"  of  ocean  steamers. 

There  are  four  boilers,  each  15  feet  in  diameter,  and  carrying  a 
working  pressure  of  75  lbs.  per  square  inch,  a  hydraulic  test  having 
been  applied,  as  is  usual  in  such  cases  to  double  the  working  pres- 
sure, viz.  150  lbs.  per  square  inch.  The  shell  plates  are  treble 
rivetted  in  the  longitudinal  seams,  and  double  rivetted  in  the  cir- 
cumferential seams.  The  furnaces  are  double  butt  strapped  (see 
A,  A  in  Fig.  39  A  on  opposite  page),  and  welded  for  a  length  of  10  inches 
at  each  end.  The  stays  B,  B  are  2^"  diameter,  and  are  spaced 
14^"  apart.  The  tubes  are  3)^"  diameter  and  7  feet  long,  arranged 
vertically  one  over  the  other  as  shown  in  the  figure.  The  total 
heating  surface  of  the  four  boilers  is  15,176  square  feet,  and  the 
total  grate  surface  is  540  square  feet. 

It  will  be  seen  from  the  dimensions  on  Fig.  39  B  that  the 
thickness  of  the  plates,  which  are  of  iron,  vary,  the  thickest  part  of 
the  shell  being  i^",  and  the  end  plates  from  y^!'  at  the  tubes 
to  if"  above  these  and  where  the  stay  rods  are  affixed. 

These  boilers  supply  steam  to  three-cylinder  compound  inverted 
engines  working  up  to  6000  indicated  horse-power,  which  are 
illustrated  and  described  under  Marine  Engines. 


BOILERS   FOR   MARINE   PURPOSES. 


77 


Fig.  39A. — Vertical  Section  of  one  of  the  Boilers  of  the  S.S.  Parisian. 


Fig.  39B. — Lonjjitudinal  Section  of  one  of  the  Boilers  of  the  S.S.  Parisian. 


yS  MODERN   STEAM   PRACTICE. 


THICKNESS    OF   PLATES,    &c.,    FOR  COAL   BOXES. 

Thickness  of  Side  Plates, ^  inch. 

Do.  Bottom, -^-^    ,, 

Do.  Corner  Angle-iron, i)^xi^xX    »> 

Do.  Stay  Angle-iron, 2X2X^    „ 

Stayed  every  3  feet  apart. 

For  Coal  Stowage  allow  46  cubic  feet  per  ton. 


PRIMING. 

Impurities  in  the  water  used  is  no  doubt  the  chief  cause  of 
priming,  and  the  evil  is  much  increased  by  the  want  of  proper 
circulation.  We  are  apt  to  crush  into  small  space  a  number 
of  tubes,  without  ever  considering  how  die  water  is  to  circulate 
around  them.  A  continual  ebullition  goes  on  in  all  directions,  the 
globules  of  steam  are  hurried  through  and  between  the  water  spaces 
in  their  passage  upwards,  and  the  water  is  allowed  to  fill  up  the 
cavity  as  best  it  can.  A  simple  experiment  on  a  kitchen  fire  will 
clearly  point  out  how  this  frothing  of  impure  water  occurs.  Take  a 
vessel  partially  filled  with  pure  water,  place  it  on  the  fire,  and  the 
water  will  boil  without  flowing  over;  but  fill  the  vessel  half  full  of 
potatoes,  with  just  sufficient  water  to  cover  them,  when  the  water 
has  boiled  for  some  time  a  slight  scum  will  be  raised,  and  the  water 
having  thus  become  impure  from  matter  extracted,  will  eventually 
overflow.  This  process  is  greatly  accelerated  by  the  small  water 
spaces  between  the  potatoes,  the  water  having  little  or  no  circulation 
downwards.  The  tubes  in  a  boiler  fill  up  the  water  space  in  a 
similar  way,  and  when  the  globules  of  steam  are  shooting  in  all 
directions  there  is  no  time  for  the  water  to  circulate  freely.  It  is  a 
good  plan  to  confine  the  great  ebullition  to  those  parts  where  the 
steam  is  more  rapidly  raised,  by  simply  fitting  circulating  plates 
between  the  tubes  and  the  side  of  the  boiler  and  other  parts,  thus  the 
space  left  between  the  circulating  plates  would  be  comparatively 
free  from  ebullition,  and  the  surface  water  in  the  boiler  would  flow 
down  and  circulate  upwards  amongst  the  tubes.  Were  such  plates 
fitted  loosely  over  the  furnace  crowns,  allowing  the  steam  to  escape 
freely  at  the  top,  the  ebullition  would  be  very  great,  the  water  circu- 
lating rapidly  between  the  plates  and  the  furnaces  would  tend  in 
a  great  measure  to  prevent  scale  forming.  The  part  mostly  afi"ected 
by  the  want  of  good  circulation  is  the  bottom  of  the  tube-plate  at 


TREATMENT   OF   STEAM.  79 

the  back  of  the  boiler,  and  the  great  heat  at  this  part  soon  cracks  the 
plate,  if  the  scale  that  rapidly  forms  is  not  frequently  removed.  Of 
course,  where  water  from  a  surface-condenser  is  used,  little  or  no 
deposit  is  formed  over  the  heating  surfaces;  but  even  with  surface- 
condenser  water,  it  is  found  necessary  to  allow  a  slight  film  of 
deposit  to  form,  otherwise  the  corrosion  that  rapidly  sets  in  would 
corrode  the  plates  very  quickly.  As  we  cannot  prevent  the  water 
frothing  up  when  it  is  taken  into  the  boiler  in  an  impure  state, 
we  must  simply  consider  the  best  means  to  prevent  the  water  priming 
over  into  the  cylinders.  With  a  good  height  of  steam-chest,  and 
with  the  steam  taken  from  the  highest  point,  the  bubbles  of  water 
will  be  broken  up  before  reaching  the  top  of  the  inside  steam-pipe 
in  the  boiler,  and  when  a  slotted  pipe  is  carried  along  the  top  of 
the  boiler,  perforated  with  a  number  of  slits  -^  inch  wide,  should  the 
globules  of  steam  and  water  reach  that  height,  as  they  cannot  pass 
through  the  slits,  they  are  broken  up,  liberating  the  steam,  which 
finds  its  way  through  the  slits  into  the  pipe,  while  the  water  con- 
tained in  the  spheres  falls  down  amongst  the  water  in  the  boiler, 
with  the  additional  advantage  that  the  steam  is  taken  away  directly 
from  over  the  surfaces  where  it  is  generated.  However,  when  no 
priming  takes  place,  a  certain  amount  of  water  will  be  carried  along 
with  the  steam;  and  when  the  steam-pipe  is  at  one  point,  the  atoms 
are  all  converging  to  that  point,  and  the  mere  mechanical  friction 
of  the  atoms  of  steam  rubbing  against  one  another  tends  to  carry 
water  through  the  steam-pipe  into  the  cylinders,  therefore  the  steam 
should  be  partially  dried  by  an  apparatus  we  will  now  explain. 


TREATMENT    OF    STEAM    FROM    THE    BOILER   TO 
THE   CYLINDER. 

Steam  generated  from  ordinary  boilers  is  far  from  being  a  pure 
gas,  properly  speaking,  it  is  quite  dry  and  invisible.  The  vapour 
blowing  off  from  the  safety-valve  shows  a  transparent  ring  near  the 
orifice  of  the  valve;  this  ring,  however,  soon  widens,  and  mixing 
with  the  cold  atmosphere,  takes  the  form  of  a  misty  vapour,  highly 
charged  with  watery  particles;  this  vapour  is  soon  dispelled,  and 


3o  MODERN   STEAM   PRACTICE. 

nothing  but  pure  water  falls  to  the  ground  in  a  gentle  shower.  Thus, 
wherever  the  steam  comes  in  contact  with  cold  surfaces  in  its  passage 
to  the  cylinder,  condensation  takes  place,  and  it  is  robbed  of  an 
amount  of  heat,  and  consequently  pressure,  thus  wasting  much  valu- 
able fuel. 

The  saturation  of  steam  with  watery  particles,  however,  is  not 
entirely  due  to  condensation,  as  there  are  various  other  causes  at 
work;  for  instance,  when  the  steam -room  in  a  boiler  is  not  of 
sufficient  height  above  the  water  in  the  boiler,  the  violent  ebullition 
that  goes  on  has  a  tendency  to  surcharge  the  steam  with  water. 
Again,  if  the  steam  is  taken  away  from  one  end  of  the  boiler,  instead 
of  from  immediately  over  the  parts  where  it  is  generated,  the  same 
result  takes  place,  the  atoms  rubbing,  too,  against  one  another,  in 
flowing  towards  one  point,  has  a  great  tendency  to  charge  the  steam 
with  water.  Violent  priming,  whether  from  the  want  of  circulation 
of  the  water  in  the  boiler,  owing  to  defective  construction,  or  by  a 
sudden  change  of  water  injected  into  the  boiler,  surcharges  steam 
with  water  to  an  aggravated  degree.  When  the  boilers,  steam-pipes, 
and  cylinders  are  not  properly  clothed,  condensation  takes  place,  and 
watery  particles  will  be  mixed  with  the  steam  to  a  large  extent,  thus 
reducing  its  pressure. 

Many  schemes  have  been  devised  to  superheat  the  steam  in 
marine  boilers  by  the  waste  heat  in  the  smoke-box,  or  uptake,  with 
the  view  of  delivering  it  into  the  cylinder  in  a  dry  state.  Many 
of  these  superheaters  have  been  fitted  to  boilers  defective  in  con- 
struction. Some  authorities  are  of  opinion  that  the  best  place  for 
drying  the  steam  is  in  the  boiler  itself,  drawing  it  from  high  steam- 
chests  and  uptakes,  thus  the  steam  is  taken  away  at  a  greater  height 
from  the  level  of  the  water  in  the  boiler,  while  the  heated  gases  from 
the  tubes  have  time  to  act  on  the  lofty  uptake  contained  in  the 
steam-chest,  and  drying  the  steam  sufficiently  for  all  practical  pur- 
poses. In  many  cases  it  is  not  convenient  to  form  lofty  steam- 
chests,  and  then  other  means  must  be  adopted  for  drying  the  steam, 
separate  vessels,  termed  superheaters,  being  used  for  that  purpose. 
The  steam  dried  by  such  contrivances  generally  receives  80°  of 
superheat  above  the  temperature  of  the  steam  in  the  boiler,  this  is 
considered,  with  fine  lubricants,  a  good  working  temperature,  that  is 
to  say,  steam  of  60  lbs.  pressure  has  295°  Fahr.,  thus  the  total  tem- 
perature will  be  295°  +  80°  =  375°  Fahr. ;  but  it  should  be  borne  in 
mind  that  the  best  oil  or  grease  must  be  used  as  the  lubricant,  other- 


TREATMENT   OF   STEAM. 


Fig.  40. — Cylindrical  Superheater. 


wise  the  dry  steam  hardens  the  oil,  to  the  detriment  of  the  piston 
and  shde-valve  rubbing  surfaces. 

Some  engineers  consider  that  when  the  steam  is  superheated, 
it  should  be  mixed  with  the  steam  in  the  boiler;  little  advantage 
exists,  however,  in  this  arrangement,  for  it  appears  a  very  doubtful 
proceeding  to  heat  up  the  steam,  and  then  rob  it  of  a  portion  of 
the  heat  by  mixing  it  again  with  steam  from  the  boiler.  The  main 
thing  to  be  studied  is  to  give  the  steam  a  sufficient  degree  of  super- 
heat, so  that  in  its  passage  to  the  cylinder  it  may  not  be  cooled 
down  below  the  temperature  existing  in  its  primary  state  in  the 
boiler,  thus  steam  in  a  dry  state  is  passing 
into  the  cylinders,  whereas  without  some 
contrivance  for  drying  the  steam  in  the 
boiler,  or  in  the  superheater,  an  admixture 
of  steam  and  water  presses  on  the  piston, 
tending  to  diminish  the  power  and  increase 
the  consumption  of  fuel. 

The  various  forms  of  superheaters  may 
be  classed  just  as  are  steam-boilers.  The 
plain  cylindrical  form  has  an  outer  shell, 

containing  a  single  large  tube,  the  inner  tube  being  stayed  with  rings 
of  angle-iron ;  where  double  round  boilers  are  used,  firing  fore  and 
aft,  the  part  fitting  on  to  the  boiler  is  bevelled,  while 
the  other  end  that  joins  on  to  the  funnel  is  quite 
square ;  these  superheaters,  four  in  number,  converge 
to  one  point,  to  which  a  single  funnel  is  fitted,  the 
bottom  part  of  the  funnel  or  the  uptake  being 
bevelled  to  suit;  this  form  of  superheater  is  simply 
effective,  and  easily  constructed,  while  the  scale  can 
be  readily  cleaned  out,  and  as  it  lies  at  a  consider- 
able angle  the  heat  acts  better  on  the  surfaces. 

Some  superheaters  of  this  class,  however,  are  placed 

vertically,  and  it  is  an  object  with  the  designer  to 

arrange  passages  so  that  the  steam  travels  up  and 

down  within  the  superheater,  time  being  required 

to  dry  the  steam   thoroughly.     The    passages    are 

formed  with  plating  rivetted  vertically  between  the 

inner  and  outer  shells,  one  of  these  plates  is  rivetted 

to  the  bottom  and  sides,   another  to  the   top  and  sides,  and  so 

on  alternately;  but  at  the  top  and  bottom  alternately  the  vertical 

6 


u 

J 

u 

L 



Fig.  41. — Cylindrical 

Superheater,  with 
division  plates. 


82  MODERN   STEAM   PRACTICE. 

plates  are  not  carried  to  the  ends  of  the  superheaters,  an  opening 
being  left  at  these  points;  thus  between  the  inner  and  outer 
shells  cellular  compartments  are  formed,  the  steam 
coming  in  at  the  bottom  of  one  cell  travels  upwards, 
and  then  descends  into  another  compartment,  and  so 
on  according  to  the  number  of  compartments,  until  it 
is  finally  carried  away  by  the  steam-pipe,  the  heated 
gases  in  this  arrangement  acting  on  the  inside  tube, 
the  outside  shell,  and  the  lower  end-plate,  all  of  which 
are  contained  within  the  bottom  part  of  the  funnel. 

Again,  we  have  a  vertical  superheater  of  the  cylindri- 
cal class,  but  instead  of  one  large  tube  passing  through 
it,  a  series  of  small  tubes  are  securely  rivetted  to  the 
Fig.  42.— Tubular  cnd-platcs,  thus  forming  a  multitubular  superheater; 
Superheater  again,  time  is  required,  so  it  is  necessary  to  place 
division  plates,  rivetted  to  the  sides  and  one  end,  having  an  open- 
ing at  the  other  end,  thus  the  steam  being  admitted  at  the  top 
passes  downwards,  flowing  all  round  the  small  tubes,  and  then 
upwards  in  the  other  compartments  according  to  the  number  of 
division  plates  fitted,  until  it  passes  into  the  steam-pipe  to  the 
cylinder.  Sometimes  the  multitubular  type  has  the  tubes  lying 
horizontally,  and  division  plates  so  disposed  that  the  steam  from 
the  boiler  enters  at  the  bottom,  passing  through  the  small  tubes, 
then  returning,  and  finally  passing  through  the  top  rows,  thus  the 
steam  goes  three  times  through,  from  the  point  where  it  enters 
the  superheater,  at  the  bottom,  to  that  point  at  the  top  on  the 
opposite  side  where  it  is  taken  away  by  the  steam-pipe.  In  plan 
this  arrangement  has  the  tubes  at  the  central  part,  the  tube-plates 
being  inclosed  with  a  circular  shell,  and  the  tubes  arranged  in 
vertical  rows.  At  the  middle  and  sides  there  is  space  left  so  that 
the  heated  gases  are  not  so  much  obstructed  as  when  passing 
between  the  tubes;  this  makes  a  very  effective  arrangement,  and 
may  be  reckoned  a  good  example  where  time  is  required. 

Many  examples  of  tubular  superheaters  have  been  fitted  directly 
on  the  tube-plate,  some  arrangements  having  the  tubes  merely  a  con- 
tinuation of  the  tubes  in  the  boiler,  the  pitch  of  the  tubes  in  the  super- 
heater being  identical.  With  this  plan  time  is  sacrificed  and  surface 
adopted ;  however,  in  some  cases  the  tubes  are  laid  the  long  way  of 
the  smoke-box,  having  boxes  at  each  end,  one  end  in  communi- 
cation with  the  steam-space  in  the  boiler,  and  the  other  with  that  of 


TREATMENT   OF   STEAM.  S^ 

the  steam-pipe  to  the  cylinder.  In  some  instances  three  boxes  have 
been  fitted  to  the  superheaters,  involving  four  tube-plates,  the  tubes 
running  right  and  left  from  the  central  box;  the  steam  from  the 
boiler  enters  this  centre  compartment,  passes  right  and  left  through 
the  tubes,  and  is  taken  away  with  separate  steam-pipes  at  each  end. 
Sometimes  the  superheater  forms  part  of  the  boiler;  and  for  low 
boilers  for  marine  purposes  this  plan  has  certain  advantages,  the 
tubes  are  arranged  vertically,  and  are  secured  into  tube-plates,  run- 
ning the  entire  length  of  the  smoke-box,  the  lower  tube-plate  being 
a  few  inches  above  the  tubes  in  the  boiler,  while  the  top  tube-plate  is 
placed  a  few  inches  from  the  top  of  the  shell  of  the  boiler.  The  steam 
from  the  boiler  enters  the  superheater  through  a  number  of  small 
apertures,  these  take  a  downward  course;  a  division  plate  being 
fitted,  the  steam  passing  this  plate  ascends,  and  is  taken  away  by 
the  main  steam-pipe;  there  are  certain  advantages  connected  with 
this  arrangement,  though  the  main  one  simply  consists  in  doing 
away  with  a  good  deal  of  piping,  as  the  steam  from  the  boiler  enters 
the  superheater  directly.  The  great  desideratum  to  attend  to  in 
tubular  superheaters  is  provision  for  cleansing  them  from  the  soot 
in  the  smoke  passages,  whether  arranged  internally  or  externally; 
some  mode  of  access  must  also  be  provided  to  the  steam  space  for 
cleansing  away  the  scale  that  rapidly  forms. 

To  employ  a  large  flat  surface,  giving  time  to  the  steam  to  be 
thoroughly  dried,  is  certainly  the  correct  principle  to  be  studied, 
when  superheaters  require  to  be  placed  in  small  space,  though  the 
complication  entailed  renders  many  arrangements  of  flat  flue  super- 
heaters not  at  all  to  be  commended  in  practice.  Vertical  flat  flues, 
similar  in  construction  to  the  overhead  flue  boiler  with  U-shaped  end- 
pieces,  and  the  plates  flanged  at  the  ends,  for  uniting  them  to  the  tube- 
plates,  all  of  which  are  inclosed  in  a  suitable  casing,  properly  and 
securely  stayed,  with  stay-bolts  and  ferrules,  is  an  effective  arrange- 
ment of  the  kind ;  the  heated  gases  pass  through  the  elongated  tubes, 
while  the  steam  is  admitted  at  one  end  of  the  casing,  and  passes 
between  the  spaces  left  betwixt  the  flues,  and  is  taken  away  by  the 
steam-pipe  placed  on  the  opposite  end  of  the  casing.  This  plan  of 
superheater  is  expensive  in  first  cost,  and  complicated  in  its  many 
parts  in  the  event  of  repairing  it  and  keeping  the  apparatus  in 
thorough  working  order.  In  all  cases  where  separate  superheaters 
are  used  for  marine  purposes,  a  stop-valve  and  pipe  must  be  fitted 
for  each  boiler,  for  shutting  off,  or  allowing  the  steam  free  access  to 


84.  MODERN   STEAM   PRACTICE. 

the  superheater.  One  stop-valve  is  fitted  to  the  superheater  for 
regulating  the  steam  to  the  cylinders,  while  in  connection  with  this 
stop-valve  and  pipe  there  is  fitted  a  stop-valve  on  each  boiler, 
having  a  pipe  connected  to  the  main  steam-pipe,  thus  in  the  event 
of  anything  going  wrong  with  the  superheating  apparatus,  all  the 
stop-valves  connected  to  the  superheater  can  be  closed,  and  the 
steam  taken  from  the  boiler  in  the  usual  manner.  This  will  show 
how  much  more  preferable  it  is  to  form  high  steam-chests  and  up- 
takes; thus  complication  is  reduced  to  the  minimum,  while  at  the 
same  time  the  steam  is  efiectively  dried.  Superheaters,  in  all  cases 
when  made  separate  vessels  from  the  boiler,  should  be  fitted  with  a 
safety-valve,  of  ample  size;  this  is  to  prevent  rupture,  as,  in  case  all 
the  stop-valves  are  shut,  a  certain  amount  of  moisture,  or  even 
steam,  is  in  the  superheater  when  the  valves  are  closed,  and  this 
would  generate  a  highly-explosive  dry  gas,  or  steam  proper,  were  the 
safety-valve  not  relieving  the  superheater  from  the  accumulating 
pressure.  In  the  absence  of  steam  in  the  superheating  vessels,  the 
injurious  effect  of  the  waste  heat  passing  up  the  chimney  acting 
upon  the  dry  plates  and  small  tubes  need  scarcely  be  pointed  out. 

In  concluding  this  brief  sketch  of  superheaters,  that  have  all  been 
practically  tried  more  or  less,  it  may  be  stated  that  for  pressures  ot 
60  lbs.  per  square  inch  in  the  boilers  the  simplest  arrangement  that 
is  found  in  practice  to  suit  all  requirements  is  a  circular  shell  fitted 
with  an  internal  flue.  The  surface  exposed,  or  total  surface  of  the 
internal  flues,  in  this  system  is  i'3  square  foot  for  every  nominal 
horse-power  the  engine  is  calculated  for;  but  for  low-pressure  steam 
the  surface  is  generally  i  square  foot  for  every  indicated  horse-power 
the  engine  works  to;  or  otherwise  from  3  to  4  feet  square  per  norninal 
horse-power  is  reckoned  amply  sufficient  for  the  superheating  sur- 
face, as  usually  arranged,  for  pressures  varying  from  20  lbs.  to  30  lbs. 
steam  in  the  boiler. 

We  will  now  consider  the  different  points  to  be  attended  to  in  the 
arrangement  for  conveying  the  steam  from  the  boiler  to  the  cylinder. 
With  the  view  of  keeping  the  steam  as  free  as  possible  from  watery 
particles,  as  has  already  been  discussed  in  the  section  on  priming, 
a  pipe  is  fixed  to  the  interior  of  the  boiler,  perforated  throughout 
its  length  with  a  number  of  holes,  by  which  the  steam  is  removed 
from  over  the  parts  where  it  is  rapidly  generated.  This  pipe  should 
be  fitted  to  all  boilers,  whether  using  superheaters  or  fitted  with 
ordinary  arrangements.     The  use  of  the  separator  has  also  been 


MANUFACTURE   OF   BOILERS.  85 

explained,  fitted  to  the  steam-pipes,  for  retaining  any  moisture  that 
is  carried  along  with  the  steam,  more  especially  steam  that  has  not 
received  a  sufficient  degree  of  superheat.  The  reader  on  turning  back 
to  page  46  will  find  the  use  of  the  separator  fully  explained.  As  the 
pipes  are  made  of  copper,  which  is  a  very  good  conductor  of  heat,  it 
is  necessary  to  clothe  them  with  felt,  and  then  cover  them  over  with 
canvas,  securely  sewn  together;  the  whole  is  then  painted,  to  pre- 
sent a  neat  and  smooth  surface.  The  steam  is  still  further  treated 
in  the  cylinder  by  the  use  of  a  steam  jacket  encircling  the  cylinder 
in  all  parts  where  radiation  takes  place;  even  the  ends  and  the  covers 
of  the  cylinders  are  steam-jacketed,  and  are  still  further  protected 
with  felt,  covered  with  "lagging,"  the  technical  term  for  narrow 
strips  of  wood  that  are  firmly  secured  to  rings  of  wood  bolted  to  the 
cylinder,  ribs  being  cast  on  for  that  purpose.  Thus  it  becomes 
imperative  that  pipes  and  surfaces,  exposed  to  external  cold,  should 
be  thoroughly  protected  to  prevent  condensation  or  reduction  of 
steam  pressure.  The  boilers  are  likewise  covered  with  felt  and  wood 
lagging,  and  sheet-lead  overall,  to  prevent  radiation 


MANUFACTURE   OF   BOILERS. 

In  all  branches  of  industry  there  are  certain  methods  better 
adapted  for  carrying  on  work  than  others,  and  although  one  maker 
may  adopt  a  very  different  method  from  another,  they  may  be 
equally  successful  in  turning  out  as  good  work,  although  the  one 
may  have  expended  more  money  than  the  other  in  doing  so.  Some, 
for  instance,  adopt  modern  improvements,  and  their  plant  is  of 
modern  make;  the  punching  machine,  for  example,  being  superseded 
by  the  multiple  drilling  machine,  and  no  one  can  doubt  for  a  mo- 
ment that  drilling  the  holes  for  the  rivets  is  done  without  straining 
the  plates  so  much  as  with  the  multiple  punching  machine  forcing 
through  three  holes  at  once,  even  although  the  drilling  machine  may 
be  doing  twenty  holes  at  one  time.  The  plating  for  boilers  and 
other  work  is  now  done  with  mathematical  exactness;  the  distance 
between  the  rivets  for  ordinary  boilers,  having  ^  inch  rivets  for 
securing  the  plates,  is  2  inches  between  centre  and  centre,  and 
from  the  edges  i  inch  to  the  centres  of  the  holes;  consequently 
the  plates  should  be  ordered  with  even  dimensions. 


86  MODERN    STEAM   PRACTICE. 

Some  may  say  this  cannot  always  be  done,  so  as  to  give  a  boiler 
of  a  certain  diameter.  We  will  only  remark  that  if  the  plates  will 
not  run  evenly,  an  inch  more  or  less  does  not  affect  the  diameter 
very  much,  as  likewise  the  length  of  the  boiler  is  not  generally  so 
confined.  The  object  of  even  dimensions  is  simply  that  when  the 
plates  arrive  they  are  at  once  taken  to  the  planing  machine  to  have 
the  edges  planed,  and  then  they  are  punched  or  drilled,  as  the  case 
may  be,  the  punching  machine  being  provided  with  a  travelling 
table,  moved  along  by  hand,  the  table  having  suitable  stops,  thus 
the  machine  templates  or  sets  out  the  holes  and  punches  at  one. and 
the  same  time.  Now  this  could  not  be  done  if  the  plates  were 
ordered  of  uneven  dimensions.  Those  who  have  not  adopted  this 
plan  for  plating  for  all  kinds  of  boilers  cannot  be  aware  of  the 
great  saving  effected.  We  have  known  working  drawings  going 
into  the  workshop,  and  the  boilers  have  been  plated  haphazard, 
stock  plates  being  kept  for  that  purpose.  We  may  at  once  note 
this  plan  a  complete  barbarism.  Plates  should  be  ordered  for 
each  boiler  separately,  and  properly  marked  both  on  the  drawing 
and  on  the  plates  as  delivered  from  the  rolling  mills,  when  they 
should  be  assorted,  and  the  workman  then  knows  where  to  lay  his 
hand  on  No.  i  or  No.  13  plate,  as  the  case  may  be.  By  this  rule 
being  duly  attended  to  much  saving  is  effected.  Indeed,  a  prac- 
tised eye  can  at  once  detect  when  boilers  are  plated  haphazard 
or  regularly;  and  certainly  it  is  not  very  pleasant  to  be  told  that 
this  or  that  boiler  has  not  the  same  appearance,  owing  to  the 
irregularity  of  the  plating  as  taken  from  stock;  and  great  waste 
occurs  when  plates  require  to  be  cut  down  to  suit  a  particular  boiler. 

For  all  difficult  boilers  block  models  should  be  made,  and  all  the 
plates  set  out  and  marked,  so  that  the  workmen  can  see  at  a  glance 
what  the  work  consists  of,  the  model  giving  a  better  idea  than  a 
drawing,  and  also  standing  more  rough  handling; — the  drawing,  in 
some  cases,  never  being  required  in  the  workshop. 

All  the  plates  should  be  ordered  for  planing  the  edges;  ^  of  an 
inch  is  the  regular  allowance  for  doing  so,  not  that  so  much  is  required 
to  be  planed  ofT,  but  at  times  the  plates  are  not  so  square  at  the 
corners  as  can  be  desired.  This  method  of  planing  the  edges  saves 
a  great  deal  of  chipping,  and  the  joints  are  more  easily  caulked. 

In  plating  the  boiler  care  must  be  taken  so  that  the  flame  does  not 
act  on  the  edges  of  the  plates.  All  joints  should  be  so  laid  that  the 
flame  passes  over,  and  does  not  impinge  against  the  end  of  the 


MANUFACTURE   OF   BOILERS. 


87 


plate,  and  all  the  outside  edges  should  be  placed  downwards;  thus 
the  moisture  freely  runs  down,  and  is  not  allowed  to  collect  at  these 
parts,  preventing  the  rapid  corrosion  that  would  otherwise  set  in. 
The  drawing  should  plainly  show  all  the  laps,  to  prevent  the  work- 
men from  plating  the  boiler  incorrectly.  The  plates  exposed  to  the 
immediate  action  of  the  flame  should  be  of  the  best  description, 
more  especially  in  the  crowns  of  the  furnaces,  where  they  must  run 
lengthways,  and  all  the  joints  kept  well 
out  of  the  fire.  Sometimes  the  furnaces 
are  plated  with  butt  joints  and  strips; 
this  is  a  good  plan  for  boilers  intended 
to  carry  high-pressure  steam.  The  end- 
plates  of  rounded  boilers  are  usually 
attached  and  stayed  to  the  shell  with 
angle-iron  at  the  corners,  having  three 
or  more  flat  plate -stays,  ri  vetted  be- 
tween two  angle- irons  at  the  ends 
and  top,  dividing  the  surface  to  be 
stayed  equally.  When  the  furnaces 
are  inside  of  the  boiler  the  angle -iron 
for  joining  the  furnace  with  the  end- 
plate  is  placed  inside,  at  the  furnace 
end,  and  outside  of  the  flue-plates  at  the 
extreme  end;  but  should  the  furnace  be  underneath  the  boiler  the 
flues  must  be  joined  to  the  end-plates  with  angle-iron  outside  of 
the  flues,  or,  in  other  words,  inside  of  the  shell.  The  water  space 
underneath  the  boiler  in  this  case  will  be  more  than  in  the  former 
arrangement,  with  2^  inches  breadth  of  angle-iron,  not  less  than 
5  inches  between  the  flue-plates  and  the  outside  shell;  and  where 
two  furnaces  or  flues  are  adopted,  the  same  space  should  be  between 
them:  when  stronger  angle -iron  is  used  the  distance  may  be  the 
same,  but  the  angle-iron  will  require  to  be  flattened  or  cut  away 
at  that  point. 

Sometimes  boilers  are  ordered  to  be  flanged  in  all  the  corner  plates. 
When  so  specified,  all  the  flanges  should  have  a  bold  radius  at  the 
corners,  not  less  than  2  inches :  this  makes  a  neat  piece  of  work,  and 
the  strength  of  the  boiler  is  materially  increased.  Water  spaces, 
having  flat  sides,  should  be  stayed  together  with  ^  inch  screwed 
stays,  tapped  into  both  plates,  and  rivetted  or  fitted  with  nuts  and 
washers  outside,  as  occasion  may  require,  the  distance   between 


F'S'  43- — Plate-stays. 


88 


MODERN    STEAM    PRACTICE. 


the  stays  being  regulated  by  the  steam  pressure  used.  For  strength- 
ening the  flues  when  they  are  of  extra  size  sometimes  angle-iron 
and  manufactured  hoops  are  introduced  at  the  joints 
(see  sketch  on  page  26).  This  plan  answers  well 
where  deposits  do  not  form  rapidly;  and  although 
large  flues,  whether  oval  or  circular,  are  not  at  all 
desirable,  they  can  be  strongly  stayed  with  conical 
tubes,  having  the  water  inside  of  the  tubes,  which  are  most  efficient 
stays,  and  give  extra  heating  surface,  and  no  boiler  having  large  or 
flat  flues  should  be  without  such  a  means  of  support     The  tube- 


Fig.  44.— Flat  Iron 
Flue  Ring. 


Fig.  45. — Conical  Water  Tube-stays. 


stays  are  so  made  that  the  bottom  parts  with  flanges  can  go  through 
the  top  holes;  thus  they  can  be  fitted  to  existing  boilers  cheaply. 
Such  a  system  of  staying  must  tend  to  decrease  the  number  of 


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Fig.  46.— Flat  Fire-box. 


boiler  explosions;  but  on  no  account  should  a  boiler  so  fitted  be 
tampered  with.  For  staying  the  end -plates  of  round  boilers 
T-irons  are  sometimes  introduced,  having  long  rods  of  round  iron 
passing  from  end  to  end  of  the  boiler,  and  jointed  with  pins  and 


MANUFACTURE   OF   BOILERS.  89 

cotters  to  the  T-irons.  With  boilers  having  hemispherical  ends  it  is 
quite  evident  that  no  stays  are  required.  Flat  fire-boxes  (see  page  88) 
for  general  purposes,  and  similar  in  construction  to  the  locomotive 
type,  should  be  well  stayed;  the  inside  fire-box  can  be  made  circular 
at  the  top,  and  for  moderate  pressure  the  flat  sides  are  only  stayed 
to  the  inside  fire-box,  with  ^  inch  screwed  stays,  rivetted  on  the  out- 
side, the  distance  between  the  squares  being  6^  inches  for  50  lbs. 
per  square  inch,  to  4%^  inches  for  lOO  lbs.  steam  pressure  per  square 
inch.  The  plates  are  all  flanged  at  the  corners,  but  the  fire-box  is 
sometimes  united  to  the  outer  casing,  with  angle-iron  at  the  bottom. 
The  short  flange  pipe,  to  form  the  furnace-door  case,  strongly  stays 
the  fire-box  at  that  part. 

As  we  consider  that  this  subject  closely  affects  the  interests  of 
steam  users,  we  append  the  following  from  a  report  presented  to 
the  National  Boiler  Insurance  Company: — "A  large  number  of 
the  boilers  proposed  for  insurance  are  so  weak  in  construction 
that  some  general  remarks,  based  on  the  extensive  experience  of 
the  construction  and  working  of  all  kinds  of  steam  boilers,  will 
doubtless  be  found  useful  to  many  owners  and  makers.  Of  the 
numerous  varieties  none  are  more  generally  used  than  the  Lanca- 
shire, or  the  cylindrical  two-flued,  and  the  Cornish  one-flued  boilers, 
and  where  these  are  well  constructed,  properly  fitted  up,  and  care- 
fully attended  to,  their  performance  is  generally  satisfactory.  There 
are  various  modifications  of  these  forms,  some  of  which  are  valuable. 
In  designing  such  boilers  excessive  length,  as  compared  with  the  dia- 
meter, should  be  avoided.  Long  boilers  strain  considerably,  and 
frequently  give  great  trouble  by  leakage  at  the  rivetted  seams.  A  fair 
proportion  is  when  the  length  is  about  three-and-a-half  times  the  dia- 
meter. The  staying  of  the  end-plates,  and  the  attachment  of  the  flue- 
tubes  to  the  ends,  should  be  so  arranged  that  the  tube  may  expand 
freely,  unless  there  be  some  special  arrangement  in  the  form  of  the 
flue-tubes  to  attain  the  same  object.  Many  boilers,  otherwise  well 
made,  have  given  considerable  trouble  by  leakage  and  fracture,  owing 
to  the  severe  strains  of  unequal  expansion  to  which  their  rigid  con- 
struction exposed  them.  In  some  of  the  boilers  inspected  the  ends 
were  so  heavily  stayed,  and  so  rigid,  that  considerable  leakage  and 
occasional  fracture  at  the  ring  seams  of  the  lower  part  resulted.  In 
others  the  staying  was  so  slight  that  the  ends  were  bulged  outwards, 
and  serious  risk  of  explosion  thus  occurred.  Flue-tubes  should  never 
be  stayed  to  the  shell,  but  be  attached  at  the  ends  only.    Many  boilers 


go  MODERN    SlEAM   PRACTICE. 

have  given  serious  trouble  through  being  thus  stayed.  The  shell 
should  be  made  quite  circular,  and  the  longitudinal  seams,  which 
should  break  joint,  be  so  arranged  that  when  the  boiler  is  set  all 
those  below  the  water-line  may  be  accessible  for  examination  in  the 
flues,  and  be  clear  of  the  brick  seatings.  Many  makers  now  double- 
rivet  these  seams,  thus  materially  increasing  their  strength,  and,  when 
the  work  is  well  performed,  reducing  liability  to  leakage.  Flue- 
tubes  are  now  constructed  in  various  ways,  some  makers  preferring 
to  use  thick  plates  not  strengthened  in  any  way,  whilst  others  prefer 
comparatively  thin  plates,  but  flanging  them  at  the  ring  seams,  or 
by  welding  each  ring  of  plates  and  connecting  them  by  solid  T-iron 
hoops,  form  a  much  stronger  and  more  reliable  flue -tube.  The 
liability  to  leakage,  fracture,  and  excessive  expansion  is  thus  much 
reduced,  as  the  heat  is  more  freely  transmitted  through  the  thin 
plates.  The  cross -tubes  and  water -pockets  introduced  by  some 
makers  in  that  part  of  the  flue-tubes  beyond  the  furnace  bridge  are 
of  great  value,  chiefly  from  the  manner  in  which  they  improve  the 
efficiency  of  the  heating  surface  by  the  diversion  and  breaking  up 
of  the  current  of  gases,  whilst  they  much  increase  the  strength  of 
the  tubes  to  resist  collapse.  All  large  tubes  exposed  to  high  pres- 
sure should  be  strengthened  by  some  of  the  means  described.  Where 
the  tubes  are  formed  with  the  ordinary  lap-joints  the  longitudinal 
seams  should  break  joint,  as  a  tube  thus  made  is  much  stronger  than 
where  those  seams  are  in  a  line;  and  at  the  furnace  end  all  longitu- 
dinal seams  should  be  below  the  fire-grate  level.  The  plan  of  form- 
ing tubes  with  the  plates  longitudinally  in  narrow  strips  is  very 
objectionable,  as  the  tubes  cannot  be  made  so  circular,  and  the 
seams  above  the  bars  are  injured  by  the  action  of  the  fire,  whilst 
such  tubes  are  much  weaker  than  those  made  in  the  ordinary  man- 
ner Multitubular  boilers  should,  as  far  as  practicable,  be  so  con- 
structed that  every  part  of  the  interior  may  be  accessible  for  cleaning 
and  examination;  and  it  would  be  a  great  improvement  if  those  of 
portable  and  locomotive  engines  were  so  constructed  that  the  tubes 
could  be  drawn  out  without  difficulty,  so  as  to  allow  occasional 
inspection  of  the  internal  surface  of  the  plates.  External  flues  are 
necessary  to  stationary  cylindrical  boilers  of  this  class,  otherwise 
the  lower  seams  are  strained,  and  become  leaky  through  excessive 
unequal  expansion  of  the  boiler.  Plain  cylindrical  externally  fired 
boilers,  with  egg  or  saucer  shaped  ends,  are  preferred  by  some 
owners,  chiefly  on  account  of  their  simple  form.     Such  boilers  can 


MANUFACTURE   OF   BOILERS.  9I 

never  work  so  safely  as  a  properly  constructed  internally-fired  boiler, 
as  they  are  so  liable  to  fracture  at  the  seams  over  the  furnaces, 
through  the  excessive  alternate  expansion  and  contraction  to  which 
they  are  exposed.  The  application  of  stout  longitudinal  stays  would 
add  materially  to  the  safety  of  such  boilers.  A  variety  of  cylindrical 
vertical  boilers  are  used  in  various  iron-works.  These  boilers  are 
generally  heated  from  the  puddling  or  similar  furnaces,  the  heat 
first  entering  the  external  flues,  and  passing  thence  by  an  internal 
descending  flue-tube  to  the  chimney.  They  are  especially  liable  to 
starting  and  fracture  of  the  rivetted  seams  opposite  the  furnace 
necks,  owing  to  the  intense  heat  at  that  point;  and  where  the  feed 
water  deposits  much  sediment  the  solid  plate  is  sometimes  fractured. 
To  avoid  this  liability  the  part  referred  to  should  be  protected  by  a 
screen  of  brickwork,  or  the  boiler  set  at  a  higher  level;  the  brick- 
work may  be  so  arranged  as  to  spread  the  heat  before  it  reaches  the 
boiler.  The  bottoms  of  these  boilers  are  frequently  quite  inaccessible 
for  examination,  and  serious  corrosion  may  go  on  unknown  to  those 
in  charge.  If  the  boilers  were  supported  by  brackets  at  the  side,  or 
by  wrought-iron  plate  standards  rivetted  to  the  bottom,  so  that  a 
thin  wall  of  brickwork  would  suffice  to  form  the  flues,  the  condition 
of  the  plates  could  be  occasionally  ascertained  without  much  diffi- 
culty. 

"As  the  safety  of  boilers  depends  so  much  on  the  sufficiency  and 
condition  of  their  fittings,  a  few  remarks  thereon  will  be  useful.  It 
is  well  to  have  two  safety-valves  to  each  boiler,  as  a  check  upon  each 
other ;  one  of  them  should  be  a  dead-weight  valve,  loaded  externally, 
and  the  other  a  lever-weight  valve,  or  a  compound  valve,  which 
would  allow  the  steam  to  escape,  if  the  water  were  allowed  to  fall 
below  the  proper  level.  Safety-valves  are  frequently  met  with,  the 
levers  of  which  are  of  such  length,  that  the  usual  working  pressure 
for  which  the  boiler  was  made  would  be  much  exceeded  if  the  weight 
were  fixed  at  the  end  of  the  lever.  The  weight  should  always  be 
calculated  and  adjusted  to  hang  at  the  end  of  the  lever.  All  boilers 
should  be  provided  with  correct  pressure-gauges  for  the  guidance  of 
the  attendants.  The  glass-gauge  is  undoubtedly  the  best  and  most 
reliable  water-gauge,  and  it  is  a  good  plan  to  attach  two  gauges  to 
each  boiler.  Where  floats  are  used  there  should  be  two,  one  of 
them  fitted  with  an  alarm  whistle.  Boilers  with  internal  tubes  should 
always  be  fitted  with  glass-gauges.  Fusible  plugs  should  be  inserted 
in  the  furnace  crowns  of  all  internally-fired  boilers.     The  feed  regu- 


92  MODERN    STEAM    PRACTICE. 

lating  valve,  which  may  be  constructed  to  act  also  as  a  back-pressure 
valve,  should  always  be  placed  at  the  front  end  of  the  boiler,  within 
the  reach  of  the  attendant,  and  where  boilers  work  in  connection, 
each  should  have  a  back-pressure  valve  attached.  The  feed  water 
should  be  delivered  a  few  inches  below  the  surface  of  the  water  in 
the  boiler,  and  above  the  level  of  the  tube  crowns,  and  in  a  horizontal 
direction,  or  by  means  of  a  horizontal  perforated  pipe.  Where  the 
feed  water  is  delivered  near  or  at  the  bottom  of  the  boiler,  it  cools 
and  contracts  the  lower  plates,  whilst  those  of  the  upper  part  are 
heated  and  expanded  by  the  steam,  frequently  causing  fracture  at 
the  ring  seams  at  the  lower  part  of  the  shell.  The  feed  water  should 
always  be  heated  before  it  is  forced  into  the  boiler.  The  blow-out 
tap  at  the  bottom  of  the  boiler  should  be  so  placed  that  it  may  be 
examined  at  any  time,  so  that  any  leakage  occurring,  it  should  be  at 
once  noted;  valves  should  never  be  used,  double-gland  taps  made 
altogether  of  brass  are  far  preferable.  Stout  seatings  with  planed 
joint  faces,  suitable  for  each  fitting,  should  be  rivetted  to  the  boiler. 
All  manholes  should  be  strengthened  by  a  faced  mouthpiece,  rivetted 
to  the  boiler,  so  that  the  joint  may  be  easily  and  well  made,  and 
leakage  and  corrosion  avoided.  Steam  domes  are  unnecessary  in 
stationary  boilers ;  a  perforated  pipe  placed  in  the  upper  part  of  the 
steam-space  is  quite  as  efficient  to  prevent  priming,  and  the  boiler 
is  not  weakened.  Where  domes  are  preferable,  they  should  never 
be  of  large  diameter,  and  the  shell  plates  inside  them  should  not  be 
all  cut  away,  that  is  to  say,  the  hole  should  be  strengthened  with 
strips  left  in  the  plate.  The  setting  of  stationary  boilers  should 
always  be  intrusted  to  a  man  of  experience.  When  boilers  are 
about  to  be  set,  special  care  should  be  taken  to  thoroughly  drain  the 
ground,  that  no  dampness  may  exist  in  the  flues  to  cause  corrosion 
of  the  plates.  All  the  flues  should  be  quite  large  enough  to  allow 
a  man  to  pass  through,  so  that  every  part  may  be  accessible  for 
repairs  and  examination.  Midfeather  seatings  are  very  objection- 
able, and  no  boiler  should  be  so  set,  except  those  of  very  small  dia- 
meter, and  in  such  cases,  thick  but  narrow  iron  plates  should  be 
placed  on  the  top  of  the  brickwork  to  protect  the  boiler.  Cylindri- 
cal boilers  internally  fired  should  be  set  on  side  walls,  the  boiler 
resting  on  fireclay  blocks  made  for  the  purpose,  and  so  shaped  that 
when  built  in  place  the  bottom  of  the  side  flues  may  be  much  lower 
than  the  point  where  the  boiler  rests  on  the  blocks.  If  the  blocks 
be  properly  fitted  to  the  plates,  that  the  bearing  thereon  may  be 


MANUFACTURE   OF   BOILERS.  93 

equalized,  the  total  breadth  of  both  side  walls,  where  in  contact  with 
the  plates,  need  not  exceed  i  inch  for  every  foot  of  diameter  of  the 
boiler.  The  top  of  the  side  flues  should  be  level  with  the  crown  of 
the  flue  tube.  All  boilers  should  be  roofed  over  to  protect  them 
from  external  moisture,  otherwise  the  sides  in^  contact  with  the  flue 
brickwork  will  be  weakened  by  corrosion.  Where  flues  are  properly 
arranged  as  described,  no  serious  corrosion  could  exist  in  the  seatings 
undetected  by  a  skilled  inspector.  The  laws  for  the  prevention  of 
smoke  are  now  being  enforced  in  many  districts,  but  boiler-owners 
should  be  cautioned  against  too  readily  adopting  any  form  of  appar- 
atus which  may  be  pressed  upon  their  notice,  as  many  are  unneces- 
sarily complicated  and  expensive. 

"  It  frequently  happens  that  good  boilers  are  injured  and  serious 
risk  is  incurred  through  neglect  and  carelessness.  Where  the  feed 
water  contains  much  sediment,  and  no  cleaning  apparatus  is  in  use, 
frequent  internal  cleaning  is  indispensable,  or  the  plates  may  become 
overheated  and  injured,  whilst  the  efficiency  of  the  boiler  is  reduced. 
The  external  flues  are  in  many  cases  allowed  to  become  almost 
choked  before  being  cleaned,  and  the  boiler  plates  so  thickly  coated 
with  soot,  that  awasteful  consumption  of  fuel  is  the  result.  Some  firms, 
on  the  other  hand,  clean  their  boilers  thoroughly  about  once  a  month, 
and  are  thereby  considerable  gainers,  as  the  efficiency  of  the  heating 
surface  is  retained,  whilst  any  defects  are  at  once  discovered  and 
made  good,  which,  if  neglected,  might  entail  expensive  repairs,  or 
even  lead  to  serious  disaster.  When  boilers  are  being  restarted  after 
stoppage,  they  should  be  heated  very  gradually,  so  as  to  avoid,  as 
much  as  practicable,  the  severe  strains  of  unequal  expansion,  and 
when  at  work  the  feed  supply  and  the  firing  should  be  as  steady  and 
regular  as  possible.  Frequent  and  extreme  alterations  of  pressure, 
especially  with  high-pressure  boilers,  or  irregularity  of  any  kind,  is 
most  objectionable,  and  sometimes  really  dangerous." 

We  consider  the  foregoing  remarks  are  well  worthy  the  consider- 
ation of  steam  users,  although  we  do  not  entirely  agree  with  the 
writer  in  limiting  the  length  of  land-boilers  to  three  and  one  half 
times  the  diameter;  and  we  do  not  advocate  too  thin  plates  for 
flues,  even  though  stayed  with  hoops,  although  the  flues  are  thereby 
strengthened;  but  entirely  agree  with  him  that  conical  water  tube- 
stays  are  invaluable  for  staying  the  flues,  as  deposit  is  not  liable  to 
form,  as  is  the  case  with  the  hoops.  We  have  known  many  instances 
where  deposits   have  rapidly  formed    at   the  roots  of  the   hoops, 


94 


MODERN    STEAM    PRACTICE. 


thereby  tending  to  injure  the  plates,  by  a  thick  coating,  through 
which  the  heat  cannot  effectually  act  on  the  water,  or,  as  it  were,  the 
water  cannot  keep  the  plates  sufficiently  cool  and  in  proper  working 
condition.  This  heating  of  the  plates,  whether  from  violent  priming, 
or  from  carelessness  in  the  attendant  allowing  the  water  to  fall  below 
the  crowns  of  the  furnaces,  is  the  main  cause  why  efficient  steam- 
boilers  at  times  expiuue.  As  already  stated  at  page  32,  steei  plates 
are  now  being  used  for  boilers,  a  reduction  in  thickness  being 
thereby  effected  of  about  20  per  cent,  and  on  the  whole  weight  of 
the  boiler  about  10  per  cent. 


THE  REGULATION  OF  STEAM  BY  THE  SLIDE-VALVE, 

AS   APPLIED   TO   LAND,    LOCOMOTIVE,    AND   MARINE   ENGINES. 

The  reciprocating  motion  imparted  to  the  piston  of  the  steam- 
engine  is  caused  by  the  steam  acting  alternately  on  the  top  and 
bottom  of  the  piston;  passages,  or  ports,  as  they  are  technically 
termed,  being  formed  in  the  cylinder  to  admit  the  steam:  these  ports 
having  a  valve  so  arranged  as  to  admit  the  steam  above  and  below 
the  piston  alternately,  with  means  of  allowing  it  afterwards  to  escape 
into  the  atmosphere,  or  into  the  condenser,  as  the  case  may  be.  The 
valve  in  its  original  form  was  simply  an  oblong  box  of  cast-iron, 
open  on  the  front  or  face,  having  a  flange  all  round,  this  face  sliding 
on  a  corresponding  part  on  the  cylinder,  both  being  accurately  faced 
up,  and  made  perfectly  steam-tight,  reciprocating  motion  being  im- 
parted to  the  valve  by  a  simple  arrangement  similar  to  the  crank 
and  connecting-rod  for  the  piston.  This  valve,  from  its  peculiar 
sliding  action,  rubbing  against  a  corresponding  face  on  the  cylinder, 
is  termed  the  slide-valve.  The  older  valve  arrangements  admitted 
the  steam  during  the  entire  travel  or  stroke  of  the  piston ;  there  were 
three  ports,  two  in  the  cylinder,  one  at  the  top  and  bottom  to  admit 
the  steam  into  the  cylinder,  and  a  central  one  outside  the  cylinder 
for  the  exhaust  or  waste  steam  from  it  to  escape  into  the  atmosphere, 
or  into  the  condenser,  if  so  fitted.  When  the  valve  was  at  half 
stroke,  the  steam-ports  were  covered,  the  valve  face  for  doing  so 
being  the  exact  width  of  the  ports,  that  is  to  say,  the  steam  ones. 
It  is  quite  evident  that  at  this  position  the  piston  must  be  either  at 
the  top  or  the  bottom  of  the  cylinder,  and  as  the  crank-pin  for  the 
piston  rotates  round  a  fixed  point,  similar  to  the  crank  centre  for  the 


REGULATION    OF   STEAM.  95 

slide-valve,  the  former  drives  the  shaft  that  gives  motion  to  all  the 
minor  details,  and  as  the  slide-valve  must  be  opened  and  shut  as  the 
crank-pin  travels  from  one  end  of  its  path,  in  a  line  with  the  cylinder, 
to  the  other  end,  it  is  quite  evident  that  the  centre,  or  pin,  for  the 
slide-valve  must  be  at  right  angles  to  that  of  the  crank  centre  for  the 
piston ;  or,  more  correctly  writing,  with  the  length  of  the  eccentric 
rod  as  the  radius,  taken  from  the  centre  of  the  engine  shaft,  on  a 
horizontal  line,  sweep  the  path  of  the  centre  of  the  eccentric,  and  the 
point  intersected  on  the  circle  is  the  position  of  the  eccentric  centre 
when  the  crank-pin  is  at  the  commencement  of  the  IN  stroke.  Or 
when  the  crank  is  moving  towards  the  cylinder,  at  this  position  the 
centre  will  be  above  the  horizontal  line;  but  should  the  crank  be 
moving  oh  the  OUT  stroke,  the  centre  of  the  eccentric  will  be  below 
the  centre  line  of  the  engine. 

It  is  quite  apparent  from  the  foregoing  that  when  the  crank-pin 
has  travelled  one  half  of  its  stroke  that  the  valve  will  be  full  open ; 


Fig.  47. — Original  form  of  Valve  without  Lap. 

A,  Commencement  of  the  IN  stroke.  B,  The  point  on  crank  path  at  half  stroke.  C,  Centre  of 
eccentric  at  the  commencement  of  the  in  stroke.  D,  Centre  of  eccentric  at  half  stroke  of 
piston,     c  E,  Length  of  the  eccentric  rod.     F,  Commencement  of  the  out  stroke. 

and  that  when  the  crank-pin  has  travelled  to  the  end  of  its  path, 
or  one  half  of  the  circle  delineated  by  the  crank  centre,  that  the 
valve  has  returned,  and  covers  the  steam-ports  exactly.  At  this 
position  the  crank-pin  centre  commences  describing  the  other  half 
of  the  circle  or  path,  the  piston  is  returning,  and  the  slide-valve  opens 
the  steam-port  for  it  to  do  so,  at  the  same  time  the  exhaust  is 
becoming  free,  the  steam  which  has  acted  on  one  side  of  the  piston 
is  escaping  into  the  atmosphere  as  for  non-condensing  engines,  or 
into  the  condenser,  as  with  the  low-pressure  type;  thus  the  steam 
acts  alternately  on  the  top  and  the  bottom  of  the  piston.  It  will 
be  observed  that  the  full  pressure  of  the  steam  from  the  boiler  was 
admitted  into  the  cylinder  the  entire  length  of  the  stroke  of  the 
piston ;  this  was  wasteful,  so  it  became  expedient  to  admit  the  steam 


96  MODERN   STEAM   PRACTICE. 

for  only  a  portion  of  the  travel  of  the  piston,  or,  in  modern  phrase- 
ology, "cutting  off"  the  supply,  the  "cut  off"  being  one  fourth,  one 
half,  and  so  on,  as  might  be  determined  on,  the  remainder  of  the 
stroke  of  the  piston  being  actuated  by  the  expansive  force  of  the 
steam  in  the  cylinder.  So  it  was  found  that  by  adding  a  little  more 
width  to  the  slide-face,  keeping  the  opening  in  ports  by  valve  the 

same  area,  and  making  a  new  eccentric 
to  suit  the  required  amount  of  cut  off, 
that  the  economical  duty  of  an  engine 
was  greatly  improved.  This  addition  to 
Fig.  48.— Valve  with  Lap.  Vertical  lines   the  facc  of  the  slidc-valve  is  termed  the 

show  the  outside  lap.  /  r    1  1  •  i  a         • 

lap  of  the  valve,  or  outside  cover.  Again, 
in  high-speed  engines  it  is  found  advisable  to  give  the  valve  an  amount 
of  lead  or  opening  before  the  piston  reaches  the  end  of  the  stroke; 
this  is  required  to  check  the  piston  at  the  termination  of  each  stroke 
by  cushioning  the  moving  mass  gradually;  thus  the  piston  is  brought 
to  a  momentary  stand-still  by  the  steam  acting  upon  it  directly  from 
the  boiler.  It  will  thus  be  obvious  that  a  piston  of  great  weight  and 
high  velocity  will  require  more  lead  or  opening  by  valve  than  a 
piston  of  less  weight,  travelling  at  the  same  velocity ;  or,  on  the  other 
hand,  a  much  less  piston,  having  a  greater  speed,  may  require  the 
same  lead  as  the  heavy  piston  moving  slowly.  Were  very  little 
lead  adopted  in  such  cases,  the  moving  mass  being  suddenly  stopped 
at  the  termination  of  each  stroke,  a  succession  of  blows  would  be 
imparted  that  eventually  would  damage  the  machine,  and  the  lead 
is  simply  introduced  to  prevent  this  occurring,  and  to  secure  the 
earliest  possible  admission  of  steam,  so  as  to  obtain  a  large  port  area 
early  in  the  stroke.  The  inside  edge  of  the  valve  face  should  just 
cover  or  be  in  a  line  with  the  port,  so  that  the  exhaust  is  open  at 
the  commencement  of  each  stroke  a  linear  distance  equalling  the 
extent  of  the  outside  lap  plus  the  lead;  by  this  means  the  opposite 
end  of  the  cylinder,  or  rather  the  piston,  is  relieved  from  the  steam 
pressure,  and  the  condensation  fully  established  before  the  steam  is 
admitted  into  the  other  end  of  the  cylinder. 

In  proportioning  the  slide-valve  of  the  steam-engine,  the  lead  of 
the  valve  must  be  duly  considered,  a  little  more  opening  of  port  by 
valve  greatly  affecting  the  lap  or  outside  cover,  as  likewise  the 
length  of  the  eccentric  rod  must  be  taken  into  account;  as  a  rule, 
with  a  proper  length  of  eccentric  rod  of  not  less  than  six  times  the 
throw  of  the  eccentric,  the  versed  sine  of  the  chord  contained  by 


REGULATION   OF   STEAM.  9/ 

the  arc,  or  travel  of  the  eccentric  centre,  equals  the  opening  of  valve 
minus  one  half  of  the  lead.  This  may  be  taken  in  all  cases  to  be 
practically  correct  when  the  valve  is  worked  by  direct  means  from 
the  eccentric,  but  when  levers  and  rocking-shafts  are  interposed 
between  the  eccentric  and  the  valve,  the  versed  sine  will  be  more 
or  less,  as  the  case  may  be;  thus  supposing  the  eccentric  rod  lever 
is  longer  than  the  one  on  the  rocking-shaft  for  the  valve,  the  versed 
sine  must  be  greater  than  for  a  direct  motion,  and  vice  versa;  but 
in  all  cases  the  throw  of  the  eccentric,  or  the  circle  described  by 
the  eccentric  centre  or  pin,  the  lap  of  the  valve,  &c.,  must  be  found 
in  the  first  place  to  suit  the  cut  off  in  the  cylinder,  as  for  direct 
motion,  and  the  levers  proportioned  accordingly. 

Sometimes  the  valves  for  land-engines  are  made  double-ported ; 
this  class  of  valve  is  simply  adopted  to  reduce  the  "throw"  of  the 
eccentric,  and  secure  rapid  admission  and  cut  off  for  the  steam; 
thus  with  ports  of  the  same  length  as  for  single-ported  arrange- 
ments, we  can,  by  having  double  or  more  ports,  increase  the  area 
for  the  entrance  and  exit  of  the  steam, — a  matter  of  importance 
when  a  high  rate  of  piston-speed  is  adopted. 

When  the  valve  is  made  large,  it  is  necessary  to  relieve  it  from 
the  steam-pressure  that  tends  to  force  it  against  the  cylinder  face. 
There  are  a  variety  of  plans  for  doing  so:  some  engineers  introduce 
a  piston  working  in  a  short  cylinder,  placed  in  the  valve-casing 
cover,  connecting  the  piston  to  the  valve  by  means  of  a  vibrating 
link;  by  this  plan  it  is  lifted  as  it  were  off  the  face,  thereby  reduc- 
ing the  friction,  as  the  valve  is  partly  suspended,  and  consequently 
more  easily  moved.  Others  have  introduced  a  flexible  plate,  con- 
necting it  to  the  valve  in  like  manner,  the  spring  of  the  plate  acting 
in  a  similar  way  as  the  piston  arrangement;  both  are  acted  on  by 
the  steam  in  the  valve-casing,  pulling  the  valve  from  the  face,  of 
course,  according  to  the  amount  of  area  exposed.  However,  such 
arrangements  are  not  to  be  relied  on,  and  the  end  in  view  is  attained 
by  simpler  contrivances.  The  usual  method,  now  in  extensive  use, 
is  by  recessing  two  rings  in  the  valve-casing  cover,  and  pressing 
them  against  a  planed  face,  on  the  back  of  the  slide-valve,  by  a 
number  of  set  screws,  placed  around,  central  with  the  recess ;  these 
set  bolts  press  against  a  ring  of  iron  in  the  first  place,  then  a  plaited 
gasket  is  interposed  between  this  ring  and  the  brass  ring,  which 
presses  on  the  back  of  the  slide-valve,  thus  making  the  area  covered 
by  the  ring  perfectly  free  from  steam ;  the  valve  is  by  this  means 


98  MODERN    STEAM   PRACTICE. 

relieved  of  much  of  the  steam-pressure.  A  small  pipe  is  introduced 
through  the  valve-casing  cover,  in  connection  with  the  eduction-pipe 
on  the  cylinder,  thus  any  slight  leakage  of  steam  between  the  ring 
in  the  recess  and  the  valve  is  taken  over  into  the  condenser  when 
so  fitted. 

Other  engineers  have  constructed  the  valve  as  a  hollow  frame, 
having  merely  sides;  the  back  in  this  arrangement  being  fitted 
with  a  narrow  piston-ring  edge,  having  springs  to  keep  the  valve 
to  the  face  on  the  cylinder,  and  also  to  press  the  piston-ring  against 
the  back  of  the  valve-casing  or  the  cover.  This  is  certainly  a 
refinement,  and  so  long  as  the  rubbing  surfaces  remain  steam-tight, 
the  plan  is  to  be  commended,  as  it  is  impossible  such  a  valve,  under 
any  circumstances,  can  have  any  more  back-pressure  than  merely 
the  rubbing  surface  that  is  not  covered  by  the  piston-ring;  but  in 
the  event  of  leakage  between  the  rubbing  surfaces,  the  plan  is  not  at 
all  to  be  desired,  as  the  vacuum  would  be  impaired,  and  great  waste 
of  steam  occur.  Therefore,  when  it  can  be  conveniently  applied, 
the  plain  ring  system  appears  best,  screwing  the  ring  against  the 
back  of  the  valve,  as  such  a  plan  can  be  adjusted  at  any  time  with- 
out breaking  a  joint,  the  set  bolts  being  simply  screwed  into  tapped 
holes  in  the  valve-casing  cover;  it  must  be  borne  in  mind,  however, 
that  the  valve-gear  must  be  proportioned  to  meet  the  full  pressure 
on  the  valve,  as  at  times  the  best  arrangements  will  get  out  of 
order.  When  cast-iron  surfaces  are  adopted,  one-sixth  of  the  total 
pressure  on  the  valve  may  be  taken  for  calculating  the  strength  of 
the  valve-rod  and  adjuncts,  that  is  to  say,  if  the  faces  are  in  good 
working  order,  and  the  lubrication  properly  attended  to. 

The  position  of  the  valve  next  claims  attention.  In  all  cases 
where  practicable,  it  should  be  placed  on  its  edge,  so  as  to  drain 
or  run  off  moisture  or  water  that  may  collect  when  the  engine  is  not 
working,  a  small  valve  being  fitted  to  the  casing  for  running  it  off; 
thus  the  faces  are  kept  as  dry  as  possible,  preventing  the  corrosion 
that  would  otherwise  set  in. 

The  reciprocating  motion  imparted  to  the  valve  is  usually  obtained 
by  means  of  a  simple  eccentric,  although  cam  arrangements  at  times 
find  favour.  The  eccentric  wheel  or  sheave  has  both  a  rotatory  and 
reciprocating  motion,  its  action  is  somewhat  the  same  as  a  pin  re- 
volving around  a  fixed  centre,  such  as  the  main  crank-pin  of  the 
steam-engine;  in  fact,  a  plain  crank  and  pin  is  often  used  instead  of 
an  eccentric ;  but  when  the  line  of  eccentric  or  valve-rod  cuts  across 


REGULATION   OF   STEAM. 


99 


Fig.  49. — Eccentric  Sheave. 

A,  Centre  of  engine-shaft.     B,  Centre  of  eccentric. 

E  F,  Thickness  of  metal  round  shaft. 

c  D  equals  a  b,  multiplied  by  2. 


the  engine-shaft,  it  becomes  imperative  to  use  an  eccentric  sheave, 
over  which  is  placed  a  loose  strap,  to  which  is  attached  the  eccentric 
rod ;  thus  the  eccentric  sheave  revolves  inside  of  the  strap,  and  the 
former  being  firmly  attached  to  the 
main  engine-shaft,  communicates 
reciprocating  motion  to  the  valve 
and  its  adjuncts;  the  jointed  end 
of  the  valve  having  suitable  guides, 
so  that  the  valve -rod  moves  in  a 
straight  line.  To  set  out  the  ec- 
centric, we  will  suppose  the  dia- 
meter of  the  engine-shaft  is  given, 
and  consequently  its  centre,  which 
we  will  term  a;  draw  a  straight 
line  through  the  centre  of  circle 
delineating  the  engine-shaft,  and 
on  this  line  set  off  A  B;  this  we  will 
name  the  crank  of  the  eccentric,  the 
point  B  denoting  the  centre  from  which  the  eccentric  sheave  is 
described ;  the  distance  from  A  to  B  equals  the  outside  cover,  or  lap, 
plus  the  full  opening  of  the  port  by  valve;  then  set  off  a  proper 
thickness  of  metal  for  the  eccentric  sheave,  around  the  shaft,  and 
from  the  point  B  describe  a  circle  touching  the  periphery  of  the 
circumscribed  thickness  around  the  shaft,  and  the  circle  described 
is  the  full  size  of  the  eccentric  sheave ;  thus  the  basis  is  given  for 
constructing  the  eccentric  motion. 

The  eccentric  is  certainly  not  the  best  method  of  imparting  motion 
to  the  slide-valve,  as  cams  give  a  better  cut  off;  but  considering  the 
great  number  of  revolutions  per  minute  many  engine-shafts  revolve 
at,  it  is  the  only  motion  that  gives  satisfaction,  being  regular  and 
easy;  whereas  with  high  speeds  the  cams  impart  a  succession  of 
blows  that  would  soon  shatter  the  machine,  and  the  noise  would  be- 
come intolerable.  However,  some  steam-engines  of  the  fire-engine 
class  have  neither  eccentric  nor  cam  motion,  but  simply  an  arm 
keyed  on  the  piston-rod,  having  an  oblong  eye,  working  on  a  twisted 
flat  bar  of  iron,  thus  imparting  motion  to  the  slide-valve ;  an  arm  is 
fixed  on  the  end  of  the  twisted  bar  for  taking  the  valve-spindle, 
a  short  link  being  interposed  between,  with  the  necessary  pins, 
guides,  &c. 

Having  now  considered  some  of  the  leading  features  demanding 


lOO 


MODERN   STEAM    PRACTICE. 


thought  in  designing  the  shde-valve  gear,  attention  must  be  drawn 
to  the  beautiful  hnk-motion,  as  first  applied  to  the  locomotive, 
in  its  general  application  to  land-engines,  more  especially  to  that 

A. 


'(figiV 


Fig.   50. — Link-motion. 

A.  Centre  of  crank-pin  at  the  commencement  of  the  in  stroke.  B,  Centre  of  forward  eccentria 
c.  Centre  of  backward  eccentric.  D,  Centre  of  suspension  in  hnk.  E,  Lifting  arm.  F,  Slide- 
rod  block. 

class  of  engine  requiring  skilled  men  as  drivers,  or  those  techni- 
cally termed  engine-tenters.  In  days  long  gone  past  we  have  often 
handled  colliery  winding-engines,  and  it  required  a  great  amount 
of  patience  and  skill  to  do  it  properly;  but  now  it  is  done  in  an 
easy  and  satisfactory  manner  by  the  double  eccentrics  and  link- 
motion,  so  that  with  an  attentive  man  there  is  no  fear  of  drawing 
the  cage,  with  probably  a  living  load,  over  the  pulleys  on  the  pit- 
head frame,  as  he  can  reverse  or  stop  the  engine  with  a  single 
movement.  Indeed,  the  numerous  small  engines  handled  in  this 
manner  every  day  lifting  heavy  weights  quickly  and  under  perfect 
control,  lead  many  inquirers  to  consider  that  the  double  eccentrics 
and  link-motion  is  the  greatest  improvement  yet  contrived  in  the 
mechanism  for  actuating  the  slide-valve. 

There  has  always  been  an  amount  of  mystery  in  explaining  the 
action  of  the  double  eccentrics  and  link,  while  all  allow  that  the 
common  eccentric,  or  crank  movement,  is  very  easily  comprehended. 
The  latter  is  set  to  give  a  movement  of  the  main  crank  of  the  engine 
in  the  particular  way  required;  the  eccentric  centre  being  fixed,  the 
crank-pin  could  by  no  means  travel  in  the  contrary  direction  per  se, 
but  by  placing  a  twin-eccentric  on  the  engine-shaft  alongside  of  the 
other  one,  with  the  centre  directly  opposite,  in  relation  to  the  main 
crank,  the  backward  movement  is  obtained;  then  by  connecting 
the  extreme  ends  of  the  eccentric  rods  to  a  slotted  link,  so  that 
this  link  can  be  moved  up  or  down  at  pleasure,  bringing  the  forward 


REGULATION   OF   STEAM.  lOI 

or  backward  eccentric  rod  in  a  line  with  the  valve-spindle,  we  have 
the  power  of  moving  the  crank  IN  or  OUT,  as  while  one  eccentric 
is  in  gear  the  other  is  simply  doing  nothing;  they  have  joined 
hands,  and  are  ready  at  a  moment's  notice  for  either  going  forwards 
or  backwards,  or  by  lifting  the  rods,  and  placing  the  link  at  mid- 
way between  the  centre  of  the  eccentric  rods,  on  a  line  with  the 
valve-spindle;  thus  no  motion  is  imparted  to  the  valve,  or  but  a 
trifle,  and  in  this  position  the  steam  is  shut  off  from  the  cylinder. 
In  fact,  the  motion  of  the  one  eccentric  is  identically  opposed  to 
that  of  the  other,  and  they  can  only  move  in  contrary  directions 
to  open  the  ports  as  required ;  and  being  linked  together,  it  is  im- 
possible that  the  one  can  do  the  duty  of  the  other,  or  that  both 
combined  can  ever  fail  in  making  the  main  crank  of  the  engine 
travel  in  the  direction  required.  When  the  link  is  down,  the  top 
eccentric  may  be  named  the  driver  (as  in  the  locomotive)  for  the 
forward  motion ;  but  when  the  link  is  raised,  the  bottom  eccentric 
rod  becomes  the  driver,  while  the  top  rod  simply  moves  to  and  fro 
along  with  the  link  which  oscillates  on  the  pin  and  block  on  the 
centre  line  of  the  valve-rod,  reciprocating  motion  being  imparted  to 
the  valve  by  the  forward  or  backward  eccentric,  as  the  case  may  be. 
The  radius  of  the  link  is  found  by  placing  the  valve  and  adjuncts 
at  half  stroke,  and  the  distance  from  the  centre  of  the  pin,  for  taking 
the  valve-block,  to  the  centre  of  the  crank-shaft  is  the  radius  of  the 
link,  all  the  other  dimensions  or  lengths  being  calculated  accordingly ; 
the  point  of  suspension  of  the  link  is  generally  on  this  arc,  described 
by  the  radius  of  the  link,  placed  midway  between  the  eccentric-rod 
ends,  the  distance  between  the  eccentric-rod  ends  being  usually 
three  times  the  throw  of  the  eccentric.  When  the  link  is  drawn 
half  up,  the  lifting  arm  being  level,  the  suspending  link  should  be 
nearly  vertical,  so  as  to  equalize  the  motion;  there  are  various 
methods  of  holding  the  link  in  position,  which  will  be  treated  in 
detail  further  on. 

The  slide-valves  for  compound  engines  are  so  arranged,  that  two 
valves,  fitted  to  one  casing,  is  sufficient,  one  at  the  top  and  another 
at  the  bottom  of  the  high-pressure  cylinder,  the  port  at  the  top  and 
bottom  admits  the  steam  into  the  high-pressure  cylinder,  the  next 
port  is  in  communication  with  the  passages  for  the  low-pressure 
cylinder,  while  the  third,  or  middle  ports,  are  in  communication 
with  the  condenser;  thus  there  are  three  ports  at  the  top,  and  the 
same  number  for  the  bottom,  of  the  high-pressure  cylinder. 


I02 


MODERN   STEAM   PRACTICE. 


The  cylinders  are  arranged  side  by  side  on  the  centre  line  of  the 
engine;  the  steam,  after  doing  duty  on  the  top  of  the  small  or 
high-pressure  piston,  expands  to  the  bottom  of 
the  low-pressure  piston,  and  then  passes  into 
the  condenser;  steam  is  also  admitted  to  the 
under  side  of  the  small  piston,  from  there  to  the 
top  of  the  large  piston,  and  then  into  the  con- 
denser; two  long  ports  or  passages  are  cast  in 
the  low-pressure  cylinder,  and  there  is  a  belt 
cast  around  the  high-pressure  cylinder,  fitted 
with  a  pipe  leading  to  the  condenser.  Such  an 
arrangement,  designed  by  the  author,  was  fitted 
to  a  pair  of  engines  for  driving  the  machinery 
at  the  Royal  Gun  Factory,  Woolwich.  The 
valve  gear  was  simply  a  crank-pin  fitted  to  a 
cast-iron  disc-plate;  on  the  pin  was  secured  a 
three-cornered  cam,  described  from  the  centre 
of  the  disc -plate,  one  cross  shaft  driven  by 
bevel  wheels  and  shaft  off  the  crank 
shaft,  suited  for  both  engines.  This 
class  of  engine  requires  no  cover  on 
the  valves,  consequently  the  length 
from  the  centre  of  the  disc-plate  to 
the  pin  or  centre  of  the  cam  is  ex- 
actly the  width  of  the  exhaust-port 
into  the  low-pressure  cylinder. 
This  cam-motion  opens  the  ports 
quickly,  while  the  valve  hangs,  as  it 
were,  at  the  top  and  bottom  of  the 
stroke.  With  coupled  engines  the  cams  are  of  course  set  at  right 
angles  to  each  other,  and  as  the  weight  of  the  valves  is  considerable, 
they  are  balanced  with  a  weight,  having  a  lever  and  links  connected 
to  the  valve-spindle.  There  was  no  hand-gear,  as  factory-engines 
rarely  require  to  be  moved  by  hand,  more  especially  when  set  at 
right  angles  to  each  other. 

The  slide-valve  for  the  locomotive-engine  differs  very  little  from 
land-engines;  but  certainly  the  locomotive  type  has  arrived  at  a 
higher  state  of  perfection  than  what  is  usually  seen  in  engines  for 
ordinary  work.  The  various  schemes  for  working  the  slide-valve 
of  the  locomotive, — and  many  arrangements  have  been  tried, — have 


Fig.  SI. — Valves  for  High  and  Low  Pressure 

Combined  Engines. 

A  B,  Throw  of  the  cam.     c,  Passage  to  condenser. 
H,  High-pressure  ports.     L,  Low-pressure  ports. 


REGULATION   OF   STEAM. 


103 


resulted,  at  this  date,  in  the  universal  application  of  the  link-motion, 
with  double  eccentrics,  as  first  practically  introduced  by  the  Stephen- 
sons. 

However,  there  are  a  variety  of  link-motions;  with  some  the  links 
are  curved,  while  others  have  them  quite  straight.  Referring  to 
those  most  in  use,  namely,  those  with  the  curved  link,  attention 
must  be  drawn  to  the  various  plans  adopted  for  connecting  the 
eccentric  rods  to  the  link.    Some  arrangements  have  lugs  forged  on 


■-4 

Fis.  5= 


-Locomotive  Link-motion. 
W,  Weigh-shaft. 


the  link,  within,  and  others  without,  the  centre  line  of  the  link  for  con- 
necting the  eccentric  rods  (Fig.  52);  other  arrangements  have  no  lugs 
whatever,  but  merely  a  plain  link,  having  the  eccentric  rods  connected 
to  the  ends,  on  the  radius  line  of  the  link  (Fig.  53),  this  plan  neces- 
sitating the  eccentrics  to  have  a  greater  throw  than  in  either  of  the 
two  former  arrangements.  Some  links  are  constructed  of  two  side 
plates,  with  distance  pieces,  the  eccentric  rods  being  placed  between 
them ;  while  in  other  arrangements  the  link  is  a  solid  bar  of  iron, 


Fig.  53. — Locomotive  Link-motion. 
W,  Weigh-shaft. 

with  the  eccentric  rods  at  the  top  and  bottom  on  the  centre  line  of  arc, 
described  by  the  link.  Then,  again,  the  mode  of  lifting  and  suspend- 
ing the  link  is  by  a  lever  and  rod,  the  point  of  suspension  on  the 
link  is  on  the  arc  described  by  the  radius  line,  and  placed  half  way 
between  the  centres  of  the  pins  for  the  eccentric  rods;  thus  the  link 
and  eccentric  rods  are  raised  or  lowered  simultaneously.  With  other 
arrangements  the  link  is  not  lifted,  but  merely  oscillates  to  and  fro 


104 


MODERN   STEAM   PRACTICE. 


on  a  pin  and  suspending-rod,  having  a  fixed  centre  at  end  on  which 
the  arm  oscillates;  this  arrangement  is  complicated,  as  a  movable 


Fig.  54. — Locomotive  Link-motion, 
w,  Weigh-shaft 

rod  must  be  interposed  between  the  link  and  the  valve-rod,  with  the 
necessary  lifting  lever  and  rod  to  raise  or  lower  it  as  required  to  suit 
the  forward  and  backward  motion  of  the  engine  (Fig.  54). 

Again,  some  link-motions  differ  entirely  from  the  foregoing,  the 
link  oscillating  on  centres,  on  the  guide-bar  for  the  valve-rod,  sup- 


F'&-  55- — Locomotive  Link. 

ported  close  to  the  link,  while  the  eccentric  rods  are  connected  to 
the  sliding-block;  this  arrangement  admits  of  the  boiler  being  placed 
lower  down,  as  the  link  requires  less  head  room ;  the  link-block  is 
of  increased  length  to  insure  steadiness;  and  as  the  reversing  lever 
supports  only  the  eccentric  rods  and  link-block,  the  slide-valves  are 
more  easily  handled,  although  all  can  be  so  arranged  with  counter- 
weights to  ease  the  labour  in  reversing  (Fig.  55). 

The  great  value  of  the  link-motion  not  only  consists  in  ena- 
bling us  to  control  the  movements  of  the  engine,  but  it  is  like- 
wise admirably  adapted  for  cutting  off  the  steam  at  any  portion 
of  the  piston's  stroke,  thus  working  expansively  without  the  aid 
of  an  additional  valve  and    mechanism,  and  also  simplifying  the 


REGULATION   OF   STEAM.  IO5 

machine,  for  undoubtedly  all  motors,  especially  those  travelling 
at  such  high  speed  as  the  locomotive-engine,  should  be  as  simple 
as  possible. 

The  means  adopted  for  keeping  the  link  in  position,  to  suit  the 
grade  of  expansion  that  is  required,  is  effected  by  placing  a  lifting  arm 
on  the  weigh-shaft  that  crosses  the  engine,  having  a  rod  attached,  pass- 
ing along  to  the  starting  platform,  to  which  is  fitted  a  quadrant  and 
reversing  lever  for  taking  the  long  rod,  connected  to  the  lifting  arms, 
on  the  weigh-shaft.  The  reversing  handle  has  a  catch  and  quad- 
rant having  a  number  of  notches  cut  on  its  periphery,  so  by  pulling 
the  reversing  handle  the  link  is  raised ;  the  catch  is  then  released, 
and  being  fitted  with  a  spring,  instantly  drops  into  any  one  of  the 
notches,  thus  holding  up  the  link.  As  the  weight  of  the  links  and 
rods  is  considerable,  they  are  balanced  with  a  weight  fitted  to  an 
arm  on  the  weigh-shaft ;  thus  the  power  required  to  move  the  links 
and  rods  is  equalized  very  nearly. 

Many  well-designed  link-motions,  from  imperfections  in  the  mode 
of  suspension,  have  failed  to  give  all  the  requisites  necessary  for  a 
perfect  motion,  a  free  admission  and  release  of  the  steam  being  of 
the  first  importance.  The  lead  or  opening  of  the  port  by  valve  at 
the  commencement  of  the  stroke  should  be  equal,  or  nearly  so,  for 
all  grades  of  expansion,  both  for  the  forward  and  backward  move- 
ment; this  being  the  case,  the  release  must  follow  as  a  matter  of 
course.  It  is  often  necessary,  when  designing  a  new  arrangement, 
to  make  a  skeleton  model,  to  practically  test  the  best  position  for 
suspending  the  link,  as  the  latter  becomes  very  sensitive  should  this 
point  not  be  duly  attended  to.  However,  by  carefully  laying  out 
the  valve-gear  on  paper,  drawing  it  accurately  to  scale,  testing  by 
delineation  the  various  positions,  the  proper  point  of  suspension  can 
be  arrived  at  without  the  aid  of  the  model.  The  point  of  suspension 
of  the  link  itself  is  midway  between  the  eccentric-rod  ends,  on  the 
arc  described  by  the  radius  line,  or  nearly  so,  and  on  which  the 
suspension-rod  should  vibrate  equally  forward  and  backward.  Some 
links  are  suspended  from  the  bottom,  on  the  pin,  for  the  backgoing 
eccentric-rod ;  and  instead  of  the  valve-rod  being  guided  as  in  the 
former  examples,  a  long  rod  is  jointed  to  the  valve-spindle,  and 
supported  at  the  link  end  with  a  vertical  oscillating  arm,  having  a 
double  joint  and  pin  direct,  passing  through  the  long  rod,  the  link- 
block  working  in  a  double  joint  on  the  end  of  the  rod,  the  block 
moves  slightly  up  and  down,  following  the  arc  of  the  oscillating 


io6 


MODERN    STEAM    PRACTICE. 


'/s/yA  yj 


arm,  the  pin  for  the  arm  being  placed  as  near  the  link-block  as 
convenient. 

It  will  thus  be  seen  that  link-motions  for  the  locomotive  are  of 
three  classes.  In  the  first  the  link  moves,  or  is  lifted  vertically,  carry- 
ing the  eccentric  rods  along  with  it.  In  the  second  the  link  is 
stationary,  having  no  vertical  movement,  but  simply  oscillating  on 
the  suspending  rod,  the  valve-rod  being  lifted  and  depressed  for 
the  forward  and  backward  movements.  And  thirdly,  the  link  is 
likewise  stationary,  oscillating  on  pins  placed  on  the  valve-rod; 
the  eccentric  rods  are  connected  to  the  sliding-block  in  the  link, 
the  rods  and  block  being  raised  vertically,  so  as  to  suit  the 
forward  and  backward  movements.  The  latter  plan  appears  the 
best  motion,  as  the  action  of  the  valves  is  more  correct,  from  the 
link  being  fixed  at  the  centre,  and  the  valve-rod  guided  in  a 
straight  line. 

For  modern  marine  engines,  although  the 
long  and  short  D  slide-valves  have  almost 
become  obsolete,  they  are  at  times  still 
adopted,  the  sectional  area  resembling  the 
letter  D,  hence  the  name  given  to  this  class 
of  valve ;  with  the  long  D,  the  valve  is  cast 
all  in  one  piece,  the  steam-ports  in  the  cylin- 
der being  as  short-  as  possible.  The  steam 
from  the  boiler,  instead  of  passing  into  the 
valve-casing,  as  with  ordinary  arrangements, 
is  admitted  on  the  face  of  the  valve,  and  the 
back  or  curve  of  the  valve  is  made  perfectly 
steam-tight  by  means  of  a  plaited  gasket, 
and  packing  pieces  of  metal  inserted  in  the 
recesses  at  the  top  and  bottom;  the  steam 
exhausting  into  the  condenser  at  the  top  and 
bottom  edges  of  the  valve,  the  long  D-valve, 
from  its  great  size,  in  some  instances  ex- 
ceeding 8  feet  in  length,  was  necessarily  a 
„      ,    ^  „,  heavy  casting,   so   two   short   D-valves    are 

Fig.  56.— Long  D-Valvei.  •'  °' 

A,  Steam  from  boiler.   B,  Packing  generally  adoptcd,  held  together  by  means  of 
spaces.  wrought-iron  rods.     The  steam  is  admitted 

into  the  valve-casing  through  what,  in  ordinary  engines,  forms  the 
exhaust-port  in  the  cylinder,  and  passes  all  round  the  valve,  which  is 
made  steam-tight,  as  before  stated,  with  hemp  packing.     The  cover 


REGULATION   OF   STEAM.  10/ 

for  the  valve  is  suited  for  the  under  side  of  the  top  port  and  the  upper 
side  of  the  bottom  port,  while  the  exhaust  takes  place  at  the  top  and 
bottom  edges  of  the  steam-ports.  The  face  on  the  cylinder  is  gene- 
rally made  of  brass,  rivetted  to  the  cylinder,  v/ith  brass  pins  screwed 
into  the  cast-iron.  The  valve-gear  for  paddle-wheel  engines  is 
generally  fitted  with  a  loose  eccentric,  revolving  with  the  main 
shaft,  having  all  the  necessary  stops  on  the  eccentric  and  the  shaft 
for  the  forward  and  backward  movements,  the  eccentric  rod  end 
taking  a  lever  on  the  weigh-shaft,  fitted  with  the  usual  gab  for 
throwing  the  valve  out  of  gear,  having  a  long  lever  handle  on  the 
weigh-shaft  for  working  the  valve  by  hand.  As  these  valves  are  at 
times  very  stiff  to  move,  provision  is  made  for  securing  a  rope  to  the 
end  of  the  lever,  so  that  a  number  of  men  may  be  employed  to  shift 
them.  The  weigh-shaft  is  fitted  with  a  lever  for  the  valve  rod,  and 
another  for  the  back  balance  weight.  This  class  of  valve  was  gene- 
rally used  for  the  side-lever  engine,  and  it  is  evidently  desirable 
that  it  should  be  capable  of  being  easily  and  quickly  handled,  as 
men  pulling  at  a  rope,  perhaps  when  the  vessel  is  pitching  and 
rolling  about  in  a  heavy  sea,  is  inconvenient  and  dangerous.  A 
wheel  and  pinion,  therefore,  is  sometimes  introduced  to  secure 
greater  ease  in  working  the  valve. 

The  slide-valve  for  oscillating  engines  is  generally  of  the  same 
type  as  is  adopted  for  land  engines,  being  fitted  with  a  pack- 
ing ring  on  the  back  of  the  valve  to  relieve  it  from  much  of  the 
steam  pressure.  The  valve  mechanism  being  entirely  different  from 
any  other  class  of  engine,  the  eccentric  is  loose  on  the  shaft,  and 
fitted  with  all  the  necessary  stops  for  the  forward  and  backward 
movements.  The  eccentric  rod  is  fitted  with  a  gab  at  its  end, 
working  on  a  pin  attached  to  an  open  curved  link,  made  so  as  to 
suit  the  oscillation  of  the  cylinder;  a  rod  passing  upwards  is  forged 
along  with  the  link,  having  means  of  guiding  it  at  the  top  with  a 
bracket  fitted  to  the  head-stock  or  framing  for  the  main-shaft,  the 
link  itself  being  guided  at  the  bottom  with  suitable  slides,  fitted  to 
the  pillars  for  supporting  the  head-stock.  This  valve  gear,  in  its 
simplest  arrangement,  has  a  plain  handle,  fitted  with  a  rod  for 
attachment  to  the  quadrant,  with  a  means  of  throwing  the  gab  on  the 
eccentric  rod  out  of  gear;  thus  the  valve  can  be  moved  very  quickly 
for  small  engines.  The  cylinder  is  usually  fitted  with  two  valves, 
but  sometimes  with  only  one;  the  double  arrangement  is  introduced 
to  balance  the  cylindei.     The  valve  spindles  have  guide-bars  forged 


io8 


MODERN    STEAM   PRACTICE. 


on  at  the  top,  fitted  with  sliding  blocks.  There  is  a  weigh-shaft, 
working  in  suitable  bearings,  placed  on  the  cylinder.  This  shaft 
sometimes  curves  round  the  cylinder,  with  a  bearing  for  each  end, 

^,- ,^  but  the  general  plan  is  to  forge 

."'''  ^N^  in  one  piece  the  levers  for  taking 

the  valve  rod  and  quadrant,  in- 
troducing a  long  bearing  between 
them,  oscillating  on  a  single  jour- 
nal fitted  to  the  cylinder.  Both 
ends  of  the  levers  for  taking  the 
quadrant  and  valve  spindle  are 
fitted  with  pins  and  loose  sliding 
blocks.  Where  but  one  valve  is 
fitted,  the  centre  of  the  pin  in  the 
lever  for  the  sector  end  is  placed 
on  the  centre  line  of  the  engine. 
When  the  valve  is  at  half  stroke, 
the  levers  being  at  right  angles 
to  the  centre  line  of  the  valve 
spindle,  the  distance  from  the 
-|-  -  centre  of  the  pin  to  the  centre 
line  of  the  trunnion  for  the  cylin- 
der is  the  radius  of  the  link  or 
sector.  Two  valves  are,  how- 
ever, generally  adopted,  necessi- 
tating the  blocks  for  the  sector 
being  kept  slightly  apart;  then  the  radius  for  the  sector  is  measured 
from  the  centre  of  one  of  the  pins  to  the  centre  of  the  trunnion. 
Thus  it  is  evident  that  the  arc  of  the  sector  must  sweep  the  centres 
of  both  pins  on  the  levers,  however  far  distant  from  each  other  they 
may  be  placed. 

The  hand-gear  for  small  power  is  simply  a  lever,  with  link  attach- 
ment to  the  sector,  but  for  heavy  engines  a  hand-wheel  and  pinion, 
working  in  a  rack  connected  to  the  sector,  is  usually  adopted; 
while  other  arrangements  have  double  eccentrics  and  link  motion, 
with  suitable  pin  and  block  fitted  to  the  sector,  at  a  convenient  place 
as  near  to  the  centre  of  the  sector  as  practicable.  The  valve  levers 
in  connection  with  the  quadrant  being  placed  at  the  half  travel  of 
the  valve,  the  vertical  distance  from  the  centre  of  the  guide-block 
pin  on  the  quadrant  to  the  centre  of  the  main  shaft  is  the  radius  of 


Fig.  57. — Valve  Motion  for  Oscillating  Engines. 

A  A,  Sector  slide  blocks.       B,Pin  for  the  gab  end  of 
eccentric  rod. 


REGULATION   OF   STEAM.  IO9 

the  reversing  link.  The  forward  and  backward  movement  of  the 
link  is  actuated  by  a  starting-wheel  working  a  worm-wheel  and  sector, 
the  shaft  for  carrying  the  sector-wheel  being  fitted  with  levers  and 
rods  for  connecting  to  it.  Although  the  link  motion  and  gear  for  the 
oscillating  engine  is  somewhat  complicated,  the  action  of  the  double 
eccentrics  and  link  is  similar  to  the  locomotive;  each  must  be  set 
identically  the  same  in  relation  to  the  main  crank  of  the  engine; 
the  only  difference  necessarily  existing  is  the  sector  for  communi- 
cating motion  to  the  valves,  and  at  the  same  time  accommodating 
itself  to  the  vibration  of  the  cylinder. 

For  direct-acting  horizontal  marine  engines  the  valve  now  gen- 
erally adopted  is  of  the  multiple- ported  type,  having  the  ports 
double  or  in  some  cases  in  triplicate.  This  valve  was  introduced 
so  that  a  large  opening  of  port  by  valve  could  be  obtained,  with 
a  moderate  throw  of  eccentric,  thus  reducing  the  size  of  the  eccen- 
trics and  gear  into  as  small  a  compass  as  possible.  The  valve 
is  usually  placed  on  its  edge,  so  that  it  is  worked  directly  from  the 
engine  shaft  by  double  eccentrics  and  the  link  motion.  Some 
engineers  place  the  valves  on  the  top  of  the  cylinder,  working  them 
with  a  system  of  wheel-gearing  similar  to  the  back  motion  of  a 
turning  lathe;  the  valve  spindles  are  connected  by  suitable  rods 
to  a  revolving  crank  shaft,  then  by  a  series  of  wheels  driven  off  the 
main  shaft  of  the  engine,  so  by  shifting  the  position  of  the  two  inter- 
mediate wheels  the  relative  position  for  the  forward  and  backward 
movement  is  obtained  in  relation  to  the  main  crank  of  the  engine. 
This  motion,  somewhat  modified,  is  considered  by  some  authorities 
as  perfect  a  motion  for  actuating  the  slide-valve  as  can  be  conceived, 
although  the  wheel-gearing  is  very  objectionable,  and  certainly  the 
link  motion  and  double  eccentrics  is  better  calculated  for  modern 
marine  engines.  As  the  valves  for  large  engines  are  of  considerable 
size,  and  consequently  the  gearing  heavy,  and  although  only  a  portion 
of  the  dead  weight  of  the  eccentric  rods,  link,  &c.,  has  to  be  lifted, 
that,  along  with  the  friction,  is  considerable;  and  in  all  cases  where 
matter  is  to  be  actuated  by  hand,  time  must  be  had,  and  conse- 
quently power,  to  do  so, — it  is  therefore  necessary  to  arrange  proper 
mechanical  appliances  for  the  handling  of  the  valve  mechanism  of 
the  marine  engine.  The  usual  hand-wheel,  with  worm-wheel  and 
sector-wheel,  lifting  levers  and  rods,  is  by  far  the  best  plan,  as  the 
link  can  be  held  up  in  any  position,  so  as  to  work  expansively  if 
required;  but  this  is  rarely  resorted  to,  as  it  is  a  much  better  arrange- 


no 


MODERN    STEAM   PRACTICE. 


ment  to  provide  a  separate  valve  to  work  expansively,  allowing  the 
slide-valve  to  move  always  in  full  gear:  thus  the  val^^^e  faces  are 
worn  evenly.  Some  makers  have  introduced  a  cylinder  having  a 
piston  and  rod  so  connected  to  the  link  that  the  reverse  movement 
is  actuated  by  steam  pressure;  and  where  marine  engines,  such 
as  those  in  the  Royal  Navy,  require  an  expeditious  means  of  hand- 
ling, this  plan  has  a  decided  advantage  in  being  able  to  reverse 
the  engine,  or  manoeuvre  the  screw  propeller  quickly,  when  the  ship 
is  in  action. 

There  are  a  variety  of  arrangements  for  link  motions  applied  to 
the  slide-valves  of  marine  engines,  but  the  arc  of  the  link  is  described 
the  same  way  in  all  cases,  no  matter  whether  the  link  is  slotted  out, 
or  simply  solid;  when  the  valve  and  adjuncts  are  at  half  stroke,  from 
the  centre  of  the  crank  shaft  to  the  slide-valve  block,  or  centre  of 
the  pin  on  which  the  link  vibrates,  is  the  length  of  the  radius  that 

describes  the  arc  of  the  link.  Some 
examples  of  valve-gear  have  two  valve 
rods,  with  eccentric  rods  on  the  return 
principle,  one  of  the  valve  rods  being 
placed  above  and  the  other  below  the 
main  shaft  of  the  engine.  The  rods  are 
guided  on  the  condenser  with  a  long 
sliding  bar,  having  snugs  forged  on 
to  take  the  rods.     The  lifting-  lever  is 


:!^ 


Fig.  58. — Link  Motion  and  Starting  Gear  for  Marine  Engines. 


placed  on  the  top  of  the  condenser,  having  a  rod  passing  down- 
wards, taking  the  reversing  link  at  the  centre  and  on  the  arc  line; 
the  lever  shaft  carrying  a  toothed  sector,  working  into  a  worm-wheel 
placed  vertically,  having  the  starting  handle  or  wheel  horizontal. 
In  this  arrangement  the  reversing  lever  makes  a  half  revolution, 
consequently  this  mode  of  suspending  the  link  is  not  well  calculated 


REGULATION   OF   STEAM. 


in 


to  work  in  any  other  grade  than  full  gear;  but  should  it  be  desirable 
the  lifting  lever  can  be  made  longer,  and  so  arranged  as  to  travel 
merely  a  portion  of  the  circle,  keeping  the  lifting  link  nearly  vertical 
throughout.  Thus  the  suspension  of  the  link  in  this  manner  is 
better  calculated  for  working  expansively;  but  it  must  be  borne  in 
mind  that  when  the  slide-valve  works  for  any  length  of  time  in  an 
intermediate  position  it  is  apt  to  wear  a  hollow  on  the  cylinder  face. 
Instead  of  the  two  rods  for  the  slide-valve,  as  in  the  previous  ex- 
ample, with  the  return  eccentric  rod  system  retained,  one  valve  rod 
has  been  substituted,  placed  above  the  main  shaft  of  the  engine.  The 
action  cannot  be  so  good  as  with  two  rods,  owing  to  the  eccentric 
rods  working  at  a  considerable  angle,  the  proper  position  being  in 
as  nearly  a  straight  line  as  possible  with  the  valve  rods.  When  so 
fitted  for  direct  action  the  valve  rod  is  guided  with  a  suitable  cross- 
head,  placed  at  the  side  of  the  rod.  This  works  in  cast-iron  guides, 
bolted  to  the  valve-casing;  the  link  is  suspended  similar  to  the 


Fig.  59. — Link  Motion  and  Starting  Gear  for  Marine  Engines. 

locomotive  arrangements,  thus  working  expansively  by  the  link. 
The  plan  may  be  adopted  for  small  engines,  but  undoubtedly  for 
large  power  there  should  be  a  separate  valve  for  working  expansively. 
The  brackets  for  taking  the  reversing  lever  are  placed  on  the  main 
framing,  the  starting  wheel  is  on  its  edge  or  at  an  inclination;  the 
shaft  for  carrying  it  is  supported  at  both  ends,  and  is  fitted  with  a 


112  MODERN   STEAM   PRACTICE. 

worm-wheel  and  pinion.  This  gear  is  very  generally  adopted,  as 
the  link  is  locked  at  any  position  without  any  other  mechanism  for 
holding  it  up.  Some  arrangements  for  direct  action  have  the  eccen- 
tric rods  too  short;  where  it  is  not  convenient  to  get  in  a  length  of 
rod  that  is  the  radius  of  the  link,  at  least  six  times  the  throw  of 
the  eccentric,  indirect  means  are  preferable  for  working  the  slide- 
valve;  and  certainly  the  return  eccentric  rod  system,  as  before  de- 
scribed, seems  as  good  an  arrangement  for  indirect  motion  as  can  be 
devised.  It  is  essential  that  the  suspending  rod  for  the  link  should  be 
made  as  long  as  convenient:  this  is  a  very  necessary  point  to  attend 
to  when  arranging  link  motions,  as  when  the  rod  is  too  short  the 
versed  sine  of  the  chord  of  the  arc  that  it  describes  becomes  very 
great,  causing  the  link  to  have  an  up  and  down  motion,  which  sen- 
sibly affects  the  working  of  the  valves,  more  especially  when  the 
eccentric  rods  are  short.  Indeed,  when  such  faults  are  both  com- 
bined in  one  arrangement  there  is  no  truthful  action  of  the  valve 
whatever,  and  in  all  cases  this  can  be  avoided  with  proper  attention. 
It  is  quite  unnecessary  to  describe  such  malformations. 

The  modes  adopted  for  guiding  the  lifting  rod  in  a  vertical  manner 
must  next  be  considered,  and  this  apart  from  the  starting-wheel, 
as  its  position  varies  very  much,  and  is  simply  arranged  in  the  best 
locality  for  handling  the  engines,  which  undoubtedly  is  on  the  same 
level  as  the  stoke-hole,  although  some  engineers  place  the  starting 
gear  on  the  top  of  the  condenser,  or  about  the  same  height  as  it, 
thus  getting  a  good  view  of  the  machinery  in  motion.  With  bevel- 
wheels  and  cross  shafts  it  is  a  very  simple  matter  to  place  the  start- 
ing gear  in  the  most  convenient  situation;  but  all  means  should  be 
as  direct  as  circumstances  will  admit  of  In  guiding  the  lifting  rod 
for  the  link  in  a  vertical  manner  a  simple  kind  of  parallel  motion  is 
sometimes  used.  The  lifting  rod  is  suspended  downwards,  the  bot- 
tom pin  is  fixed  to  the  middle  of  a  short  link,  the  ends  of  the  link 
taking  an  arm  placed  above  and  another  below  the  lifting  centre; 
one  of  these  arms  merely  vibrates  on  a  fixed  pin,  while  the  other 
or  bottom  one  is  keyed  on  the  reversing  shaft  that  passes  across  the 
engine.  This  shaft  is  likewise  fitted  with  an  arm  for  taking  the 
reversing  rod,  passing  along  to  some  convenient  part  on  the  con- 
denser. In  this  example  the  reversing  rod  is  attached  to  a  cross- 
head  moving  in  suitable  guides,  the  starting-wheel  actuating  a  screw 
cut  in  its  shaft,  the  cross-head  having  a  female  screw  to  correspond. 
It  is  quite  essential  that  all  link  motions  should  be  balanced  with  a 


REGULATION   OF   STEAM. 


"3 


counter  weight,  keyed  and  fixed  to  an  arm  on  the  reversing  shaft 
Instead  of  parallel  motion  for  keeping  the  lifting  rod  in  a  vertical 
line,  a  plain  cast-iron  guide  is  at  times  adopted,  having  a  sliding 
block  for  taking  the  lifting  pin,  and  the  reversing  levers,  similar  to 


Fig.  60. — Link  Motion  and  Starting  Gear  for  Marine  Engines. 

the  foregoing  example,  fitted  with  a  short  link  for  connecting  the 
reversing  arm  and  sliding  block;  the  lifting  rod  being  attached  to 
the  pin  on  block  and  main  link,  doing  away  with  the  top  arm,  as  in 
the  previous  example.  In  some  designs  the  link  is  not  suspended 
for  the  forward  movement,  but  simply  rests  on  the  slide  block. 
When  the  link  is  full  down,  the  lifting  pin  on  the  arm  passing 
through  a  short  slotted  hole  in  the  rod,  the  pin  being  free  to  move  in 
the  slot  to  suit  the  vibration  of  the  link,  there  is  neither  upward  nor 
downward  movement  in  the  link,  as  it  is  always  resting  on  the  slide- 
block  for  the  forward  movement,  the  pin  in  the  elongated  hole 
accommodating  itself  to  the  versed  sine  of  the  lifting  rod.  Another 
mode  of  lifting  the  link  is  by  means  of  a  screwed  rod  placed  verti- 
cally (Fig.  61),  having  bevel-gear  overhead  in  connection  with  the 
starting-wheel.  On  the  screwed  part  of  the  vertical  shaft  at  the 
bottom  is  fitted  a  nut,  having  two  pins,  for  taking  the  short  links  thai 
are  fitted  to  the  lifting  arm,  the  lifting  rod  for  the  main  link  being 
jointed  thereto;  the  pin  is  placed  between  the  end  and  the  centre  of 
vibration  of  the  lifting  arm.  The  shaft  for  the  lifting  arm  passes 
across  the  engine,  having  merely  a  plain  lever  and  rod  at  the  other 
end  for  actuating  the  main  link. 

A  variety  of  other  examples  suited  for  the  slotted  link  as  well 

& 


114 


MODERN   STEAM   PRACTICE. 


as  for  the  solid  one  could  be  given.     Suffice  it  to  say,  however,  that 
when  solid  links  are  adopted  the  eccentric  rods  are  connected  to 


/ 


v^ 


Fig.  6i. — Link  Motion  and  Starting  Gear  for  Marine  Engines. 


the  ends  of  the  link,  one  of  the  pins  taking  the  lifting  rod  being  con- 
nected to  the  lifting  arm  with  similar  mechanism  as  for  the  slotted 
link.  However,  when  the  link  is  suspended  from  any  other  centre 
than  the  true  one,  at  or  near  the  centre  of  the  link,  the  motion  of 
the  valve  is  not  so  correct  as  with  the  plans  described  above.  For 
very  small  engines  we  would  certainly  adopt  the  usual  starting  gear 
as  applied  to  the  locomotive  engine,  having  a  plain  lever  handle 
fitted  with  a  catch,  and  quadrant  notched  to  suit  a  varying  expan- 
sion; but  of  course  this  must  only  be  used  where  the  strength  of 
one  man  is  sufficient  to  work  the  valve-gearing. 

From  the  brief  sketch  above  given  of  some  of  the  plans  most  in 
use  for  giving  motion  to  the  slide-valves  of  the  marine  engine,  it 
will  be  seen  that,  where  circumstances  admit,  the  two  former 
examples  are  the  simplest  motions,  as  having  fewer  working  parts; 
and  it  must  be  borne  in  mind  that  simplicity  in  the  machinery  on 
board  ship  is  the  main  thing  to  be  studied. 

In  concluding  this  part  of  the  subject  attention  must  be  drawn  to 
a  species  of  valve  and  gear  for  working  expansively,  termed  the 
gridiron  expansion-valve,  of  which  there  are  two  kinds;  one  being 


REGULATION   OF   STEAM. 


115 


quite  flat,  while  the  other  is  circular.  The  former  is  simply  a  flat 
plate,  having  a  number  of  slots  or  openings,  strengthened  with  ribs 
cast  on  the  back;  the  valve  is  of  brass,  as  likewise  is  the  face  it  works 
upon.  It  is  placed  as  near  to  the  main  slide-valve  as  possible.  There 
is  a  considerable  steam  pressure  on  the  flat  type,  and  to  obviate  that 


Fig.  62. — Expansion  Valve  Gear. 

A  B,  Line  of  ctank,      C,  Valve  chest.      d  e.  The  radius  of  expansion  link.      F,  Lever  end  for  ditto. 
G,  Centre  of  eccentric  at  the  beginning  of  the  stroke. 

defect  circular  valves  have  been  introduced,  one  species  being  in 
equilibrio,  consisting  simply  of  a  series  of  rings  and  openings  cast  all 
in  one  piece,  and  having  a  central  boss  with  ribs  radiating  from  the 
centre.  These  ribs  hold  all  the  rings  together,  the  openings  being 
I  inch  broad  for  large  valves;  five  of  these  openings  have  been 
adopted,  giving  ample  area.  This  valve  is  accurately  turned  to  fit  a 
similar  cylinder  of  brass,  with  openings  to  correspond,  held  together 
with  vertical  ties,  cast  all  in  one  piece — the  whole  being  encased  in  a 
cast-iron  valve  box,  having  an  annular  space  all  round.  The  steam 
from  the  boiler  passes  down  through  the  hollow  valve,  and  then  round 
the  annular  space  into  the  slide-valve  chest  on  the  cylinder.  At  the 
commencement  of  each  stroke  the  ports  are  full  open,  and  the  valve 
gear  is  so  arranged  as  to  cut  off  up  to  a  little  more  than  one-half  of 
the  stroke ;  at  least,  practically  speaking,  this  is  attained  (while  the 
slide-valve  for  the  engine  is  arranged  to  cut  off  at  five-eighths  of  the 
stroke  of  the  piston).  The  valve  gear  consists  of  an  eccentric, 
having  a  throw  of  2  inches,  the  eccentric  rod  taking  a  lever  4  inches 
in  length.  This  lever  vibrates  on  a  short  shaft,  on  which  is  fitted  a 
slot  link  with  a  movable  sliding  block,  to  which  is  attached  the  con- 


Il6  MODERN   STEAM   PRACTICE. 

necting  rod  for  the  valve  spindle.  As  the  circular  valve  depends  on 
its  fit  to  make  it  steam-tight,  it  is  evident  that  it  should  be  arranged 
vertically,  so  that  the  wear  may  be  as  little  as  possible.  To  set  out 
this  valve-gear  the  line  of  the  main  crank  is  placed  level,  the  crank 
pin  being  at  the  commencement  of  the  IN  stroke;  the  valve  is  set  full 
open,  and  at  a  point  on  the  valve  spindle,  with  a  certain  radius  to 
suit,  describe  an  arc:  this  is  the  curve  of  the  link.  It  is  evident 
that  when  the  sliding  block  in  the  link  is  moved  to  and  fro  along 
with  the  radius  rod  in  connection  with  the  valve  spindle,  the  line  of 
the  crank  being  level,  that  no  motion  is  imparted  to  the  valve,  or 
even  when  the  crank  is  revolving  the  radius  link  can  be  drawn  to  the 
centre  of  vibration  of  the  lever  shaft;  thus  the  valve  always  remains 
open  when  required,  the  lever  and  link  simply  vibrating  to  and  fro. 
The  motion  of  the  lever  is  always  constant,  travelling  in  an  arc  due 
to  the  throw  of  the  eccentric,  while  the  pin  and  block  working  in 
the  slotted  link  can  be  moved  out  at  pleasure,  giving  a  varying 
throw.  Hence  the  valve  can  cut  off  the  steam  supply  up  to  one-half 
of  the  stroke  of  the  piston;  but  from  the  nature  of  the  motion,  the 
eccentric  passing  the  dead  centre  of  its  throw,  while  the  crank  for 
the  engine  is  gaining  rapidly,  the  valve  does  not  commence  to  open 
until  the  piston  has  travelled  about  five-eighths  of  its  stroke,  when 
the  main  slide-valve  has  come  into  action,  and  consequently  no 
more  steam  can  be  admitted  into  the  cylinder.  Thus  the  expansion- 
valve  gives  a  varying  cut  off  from  the  valve-casing,  while  that  of  the 
main  slide-valve  admits  a  constant  volume  into  the  cylinder,  de- 
veloping the  full  power  of  the  engine  while  so  doing.  The  block 
and  pin  for  the  separate  expansion-valve  can  be  drawn  back  to  the 
centre  of  vibration,  leaving  the  passages  in  the  expansion-valve 
always  full  open.  This  single  eccentric  and  link  motion  for  work- 
ing an  expansion -valve  separately  from  the  main  slide-valve 
can  be  arranged  for  any  class  of  valve,  as  likewise  the  locality  of 
the  valve  in  relation  to  the  eccentric  on  the  main  shaft,  the  arrange- 
ment given  being  originally  designed  by  the  author  for  marine 
engines. 

The  geometry  of  the  steam-engine  next  calls  for  attention,  at 
least  that  portion  of  it  which  immediately  bears  on  the  subject  of 
valve  motions.  This  must  be  always  carefully  studied,  in  order  to 
determine  all  the  points  requisite  in  arranging  the  slide-valve,  the 
lap  and  lead  of  the  valve  to  suit  a  given  cut-off  in  the  cylinder  being 
of  the  first  importance. 


REGULATION  OF  STEAM.  I  If. 

THE  CONNECTING  ROD  AND  CRANK. 

The  length  of  the  connecting  rod  varies  considerably,  those  of 
direct-acting  marine  engines  being  much  shorter  than  in  other 
arrangements.  Taking  an  example,  however,  where  the  length 
equals  five  times  the  length  of  the  crank  from  centre  to  centre;  when 
the  centre  of  the  cross-head,  where  the  connecting  rod  is  attached, 
is  placed  at  half  stroke,  from  the  centre  of  the  engine  shaft  to  the 
centre  of  the  cross-head  is  the  length  of  the  connecting  rod,  delin- 


Fig.  63, — The  Connecting  Rod  and  Crank. 

A,  Centre  of  engine  shaft.       B,  Half  stroke  of  piston.       c,  Point  on  crank  path  at  half  stroke. 
D  E,  Stroke  of  piston.       f,  Point  on  crank  path  at  f^ths  of  the  stroke. 

eated  as  from  A  to  B.  With  B  A  as  the  radius  describe  the  arc  A  C, 
draw  a  straight  line  from  the  centre  A  to  the  point  C  on  the  crank 
path;  this  is  the  centre  line  of  the  crank  at  half  stroke,  the  point  C 
being  the  centre  of  the  crank  pin  above  or  below  the  centre  line  of 
the  engine.  It  will  be  seen  that  there  is  a  great  difference  of  the 
travel  of  the  crank  pin  on  its  path  for  the  IN  and  OUT  strokes,  the 
arc  described  for  the  IN  stroke  being  greater  than  that  for  the 
OUT,  as  delineated  from  IN  to  C  above  the  centre  line,  and  from 
OUT  to  C  below  the  centre  line  of  the  engine.  There  is  no  remedy 
for  this  variation;  it  is  inherent  in  all  crank  motions,  and  varies  as 
the  length  of  the  connecting  rod.  It  therefore  becomes  imperative 
to  find  the  point  c  to  suit  the  length  of  the  rod,  as  likewise  to  deter- 
mine the  point  on  the  crank  path  for  the  particular  part  of  the 
stroke  of  the  piston  that  may  be  determined  on  for  cutting  off  the 
steam.  Thus  supposing  it  is  desirable  to  cut  off  at  five-eighths  of 
the  stroke  of  the  piston,  the  arc  A  C  will  be  greater  than  for  the 
half  stroke,  and  vice  versa  when  the  point  of  cut-off  is  sooner  than 
the  half  stroke.  The  particular  point  is  easily  found  by  taking 
the  radius,  and  placing  the  point  of  the  compasses  on  the  first  point 


I. 1 8  MODERN   STEAM   PRACTICE. 

from  B  to  E,  then  cut  the  crank  path  at  F,  the  dotted  hne  A  F  is  the 
line  of  cut-off  by  crank  when  the  piston  has  travelled  five-eighths  of 
its  stroke.  This  angle  is  always  the  same,  no  matter  whether  the 
stroke  or  length  of  the  crank  is  longer  or  shorter;  that  is  to  say,  if 
the  connecting  rod  bears  the  same  proportion  to  the  crank,  namely, 
five  to  one. 

THE  CRANK  AND  ECCENTRIC  PATHS. 

The  crank  and  eccentric  paths  are  identical;  the  path  of  the  one 
is  exactly  the  path  of  the  other.  Each  revolves  around  the  same 
centre,  namely,  that  of  the  main  shaft  of  the  engine.  The  crank  and 
eccentric  centres  each  describe  an  arc,  the  length  of  the  chords 
varying  with  the  circles  described.  The  chord  A  B  described  by  the 
crank  centre  being  greater  than  that  delineated  by  the  eccentric 


Fig.  64. — The  Crank  and  Eccentric  Paths. 

A  B,  Chord  of  the  arc  of  supply  on  crank  path.  c  d,  Chord  of  the  arc  of  supply  on  eccentric  path. 
X  F,  Versed  sine  of  the  chord  of  the  arc  of  supply  on  crank  path.  G  H,  Versed  sine  of  the  chord 
of  the  arc  of  supply  on  eccentric  path.      1,  Centre  of  engine  shaft. 

centre  on  C  D,  consequently  their  versed  sines  must  likewise  vary. 
Thus,  in  the  example,  the  large  circle  denotes  the  path  of  the  crank, 
and  the  small  circle  that  of  the  eccentric ;  A  is  the  commencing  of 
the  IN  stroke,  and  B  the  point  of  cut-off  determined  on.  It  is  very 
evident  that  the  point  A,  or  crank  pin,  has  travelled  from  A  to  B, 
while  that  of  the  eccentric  has  travelled  from  c  to  D;  draw  the  lines 
A  B  and  C  D,  bisect  A  B  at  F,  and  draw  the  lines  E  F  and  G  H  through 
the  centre  I.  The  line  E  F  is  the  versed  sine  of  the  chord  for  the  crank 
path,  and  G  H  is  the  versed  sine  of  the  chord  for  the  eccentric  path. 
In  all  cases  the  versed  sine  of  the  chord  for  the  crank  path  must,  in 


REGULATION   OF   STEAM. 


119 


the  first  place,  be  found  due  to  the  length  of  the  crank  and  connecting 
rod,  as  likewise  the  point  of  cut-off;  then  when  the  versed  sine  of 
the  eccentric  is  likewise  known,  which  equals  the  opening  of  the  port 
by  valve,  minus  one-half  of  the  lead,  then  the  eccentric  circle  can  be 
found  by  the  rule  of  three  (based  on  the  known  property  that  the 
versed  sines  of  circles  of  similar  segments  are  as  the  diameters  of 
the  respective  circles).  Thus,  supposing  the  crank  circle  was 
18  inches  in  diameter,  the  versed  sine  E  F  being  4  inches,  while  the 
versed  sine  G  H  is  i  ^  inch :  we  have 

4  :  18  : :  1-25  =  562  inches  diameter  of  the  eccentric  circle. 


THE  CRANK  AND  ECCENTRIC  PATHS  DELINEATED  AS  REGARDS 
THE  COVER,  LEAD,  AND  CUT-OFF. 

The  length  of  the  eccentric  rod  being  not  less  than  six  times  the 
throw  of  the  eccentric,  the  versed  sine  of  the  chord  described  by  the 
arc  on  the  eccentric  path  equals  the  opening  of  the  port  by  valve, 
minus  one-half  of  the  lead  nearly.  Thus,  supposing  the  versed  sine 
of  the  chord  of  the  arc  of  supply  on  the  crank  path  was  4  inches, 
the  opening  of  the  port  by  valve  i  ^  inch,  and,  for  the  sake  of 
illustration,  the  lead  or  opening  of  the  port  at  the  commencement 
of  the  stroke  of  the  piston  is  ^  inch,  we  have  1%  —  ^=zij^  inch, 
the  versed  sine  of  the  chord  of  the  arc  of  supply  of  the  eccentric. 


..C.  (7>-  jtamt,  of  cut  o^ 


Fig.  65.— The  Crank  and  Eccentric  Paths  delineated  as  regards  the  cover,  lead,  and  cut-oflF. 

Let  A  B  represent  the  line  of  the  crank  at  the  commencement  of 
the  IN  stroke;  as  the  point  A  or  crank  pin  travels  from  A  to  C,  the 
point  of  cut-off,  it  is  evident  that  the  valve  must  open  and  shut 
while  the  crank-pin  centre  describes  the  arc  AC.  It  is  therefore 
necessary  to  lay  off  the  eccentric  centre  on  the  opposite  side  of  the 
path,  as  at  F.     Set  off  F  E,  which  equals  the  full  opening  of  the  port 


I20  MODERN   STEAM   PRACTICE. 

by  valve,  minus  the  lead,  or  i  inch;  this  is  the  distance  from  E  to  F. 
Then  set  off  E  D,  the  lead  equals  ^^  inch,  while  the  remainder  of 
the  radius  of  the  eccentric  circle,  or  B  D,  equals  the  outside  cover 
or  the  lap  of  the  valve.  With  the  length  of  the  eccentric  rod  as  the 
radius  from  E,  the  point  2  on  the  valve  can  be  determined ;  this, 
for  sake  of  illustration,  is  measured  from  the  edge  of  the  valve, 
instead  of  the  pin  on  the  valve  rod  for  taking  the  eccentric  rod, 
and  from  the  edge  of  the  valve,  as  at  2,  cut  the  eccentric  path  at 
2,  and  from  the  point  D  fix  the  point  3  on  the  valve;  cut  as  before 
the  point  3  on  the  eccentric  path,  join  the  line  from  2  to  3  on 
its  path;  that  line  is  the  chord  of  the  arc  of  supply  by  eccentric. 
It  will  thus  be  seen  that  the  figures  on  the  eccentric  path  cor- 
respond with  the  figures  on  the  valve;  thus  the  point  2  gives  the 
lead,  the  point  i  the  full  opening  of  the  port  by  valve,  and  at  the 
point  3  the  valve  has  returned  and  just  covers  the  port,  this  being 
the  point  of  cut-off,  or  no  more  steam  is  admitted  into  the  cylinder, 
the  remainder  of  the  stroke  of  the  piston  being  actuated  by  the 
expansive  force  of  the  steam  in  the  cylinder.  It  will  thus  be  seen 
that  when  the  crank  centre  is  at  the  commencement  of  the  IN  stroke, 
as  at  A,  the  port  is  open  ^  inch ;  when  the  crank  pin  centre  travels 
to  G  the  port  is  full  open,  and  the  valve  returning,  until  the  crank 
centre  has  travelled  to  C,  then  the  cut-off  takes  place,  the  valve 
having  closed  the  port;  thus  the  expansion  of  the  steam  in  the 
cylinder  commences.  This  only  provides  for  the  IN  stroke;  that 
for  the  OUT  stroke  must  be  found  in  like  manner,  and  it  will  be 
seen  that  with  the  same  throw  of  the  eccentric  the  opening  of  the 
steam  port  by  valve  is  less  for  the  OUT  stroke  than  for  the  IN  stroke; 
consequently  the  lap  for  the  OUT  stroke  must  be  greater  than  for 
the  IN  stroke.  When  great  nicety  is  required,  the  area  of  the  port 
on  the  cylinder  should  be  arranged  for  the  OUT  stroke,  and  the 
length  of  the  port  for  the  IN  stroke  reduced  accordingly,  so  as  to 
get  equal  area  of  port  for  IN  and  OUT  stroke,  as  likewise  equal  cut- 
off in  the  cylinder.  Thus  when  the  versed  sine  of  the  chord  of  the 
arc  of  supply  is  given  for  the  crank  path,  and  the  versed  sine  of 
the  chord  of  the  arc  of  supply  can  be  determined,  it  becomes  an 
easy  matter  for  the  student  to  practically  delineate  the  various 
points  of  the  crank  and  eccentric  paths  in  relation  to  each  other. 

To  find  the  versed  sine  of  the  eccentric  rod,  working  to  the  for- 
mula V=R — (VR^ — C^)  [V=  versed  sine,  R  =  radius,  C  =  semi- 
chord],  we  can  take  as  follows: — Throw  off  the  eccentric,  or  the 


REGULATION   OF   STEAM.  12 1 

diameter  of  the  circle  of  the  eccentric  pulley  centre,  round  the 
centre  of  the  crank  shaft  (C  X  2)  =  50  parts.  Eccentric  rod,  300 
parts  in  length  (R) ;  opening  of  port,  20  parts ;  lap,  5  parts. 

300^  =  90000;  C=25;  €'  =  625. 
Then    taking    90000 — 625  =  89375,  and  ^89375  =  299 — .     Then 
V  or  the  versed  sine  would  but  equal  300 — 299 — ;  or  i  X  :  equal 
to  but  -5V  of  the  entire  travel  of  the  valve. 

DOUBLE   ECCENTRICS   AND   LINK  MOTION. 

The  mode  of  setting  out  the  link  motion  for  the  marine  engine 
differs  but  little  from  that  pursued  for  the  locomotive  type.  With 
the  former  the  double  eccentrics  and  link  are  simply  introduced,  so 
as  to  get  a  convenient  arrangement  for  handling  the  engines,  the 
link  being  rarely  used  to  work  with  varying  expansion,  it  being 
either  full  up  or  full  down.     The  reversing  lever  in  general  makes 


XeveiZxttei 


ifBiBiiitll  : 


Fig.  66. — Double  Eccentrics  and  Link  Motion  for  the  Marine  Engine. 

a  half  revolution  around  its  axis,  the  point  of  suspension  on  the 
lever  being  either  up  or  down,  the  link  being  in  full  gear  for  the  for- 


122  MODERN   STEAM   PRACTICE. 

ward  or  backward  motions,  as  the  case  may  be.  In  some  instances 
the  lifting  or  reversing  lever  only  describes  a  small  arc  of  a  circle, 
having  the  radius  of  the  lever  much  longer  than  by  the  former 
arrangement;  then  the  point  of  suspension  is  at  some  intermediate 
part  of  the  half  circle;  in  fact,  just  similar  to  the  examples  given 
for  the  locomotive  engine  in  the  preceding  pages.  In  all  examples 
the  most  convenient  method  of  setting  out  the  link  is  by  placing 
the  valve  and  adjuncts  at  half  stroke,  A  being  the  centre  of  the 
crank  shaft,  and  B  the  centre  of  the  pin  on  the  valve  spindle  for 
taking  the  block  on  which  the  link  slides.  With  the  radius  A  B 
describe  the  arc  DD;  this  is  the  centre  line  of  the  curve  of  the 
link;  make  the  distance  between  the  pins  for  taking  the  eccentric 
rods,  as  at  E  E,  equal  to  three  times  the  throw  of  the  eccentric 
or  diameter  of  the  path.  Then  from  the  point  B,  with  a  convenient 
length  of  lifting  rod  as  the  radius,  describe  the  arc  C  F;  it  gives  the 
position  at  the  half  lift  of  the  link  of  the  reversing  lever,  or,  as  in 
the  main  connecting  rod  for  the  engine,  the  vertical  distance  from 
B  to  C  is  the  length  of  the  lifting  rod,  the  radius  of  the  lifting  arm 
C  F  being  half  of  the  distance  between  the  centres  of  the  pins  on 
the  link  for  the  eccentric  rods.  Thus  we  have  given  the  leading 
points  to  attend  to  in  setting  out  the  double  eccentrics  and  link 
motion. 

THE   LAP   OF   THE   VALVE   VARIES   AS   THE   CUT-OFF   AND 
LENGTH   OF  CONNECTING   ROD. 

With  the  opening  of  port  by  valve,  and  the  lead  remaining  the 
same,  the  lap  of  the  valve  must  vary  as  the  cut-off.  The  less  the 
,  chord  and  versed  sine  of  the  arc  of  supply  becomes  on  the  crank 
path  the  greater  is  the  chord  of  the  arc  of  supply  on  the  eccentric. 
The  figure  shows  the  chord  of  the  arc  of  supply  on  the  crank  path  in 
plain  lines,  while  the  eccentric  circles  are  delineated  by  dotted  lines. 
The  line  A  A  is  the  opening  of  port  by  valve,  while  the  curved  line 
represents  the  laps  for  the  various  points  of  cut-off.  It  will  be  seen 
that  when  the  steam  is  cut  off  at  five-eighths  of  the  stroke  of  the 
piston  that  the  valve  at  B  has  less  cover  than  at  C ;  or  when  the  steam 
is  cut  off  at  five-eighths  of  the  stroke  the  valve  requires  less  lap  than 
for  cutting  off  at  the  half  stroke  of  the  piston,  and  so  on  increasing 
the  diameter  of  the  eccentric  path.  The  diameter  of  the  sheave  like- 
wise increases  rapidly,  more  especially  when  cutting  off  at  one-eighth 


REGULATION   OF   STEAM. 


123 


part  of  the  stroke  of  the  piston,  when  we  have,  as  in  the  figure,  the 
diameter  of  the  eccentric  path  much  greater  than  the  diameter  of 
the  crank  path.     It  thus  becomes  apparent  that  the  valve  must  be 


Mmmmmfgr^m^ 


Fig.  67. — Diagram  of  the  Lap  of  Valves.  fT 

altered,  the  multiple-ported  type  being  adopted.  Thus,  by  intro- 
ducing three  steam  ports  at  each  end  of  the  valve,  with  one  central 
exhaust  port,  we  gain  the  same  area  of  port  on  the  valve,  while  the 
opening  of  each  port  is  only  one-third  of  that  of  the  single-ported 
arrangements,  so  when  the  steam  is  cut  off  at  one-eighth  or  one- 
fourth  part  of  the  stroke  of  the  piston,  a  valve  should  be  adopted 
having  three  steam  ports  at  each  end,  with  one  central  exhaust  port, 
thus  greatly-  reducing  the  stroke  of  the  valve,  and  consequently  the 
lap ;  the  lead  may  be  presumed  equal,  at  least  as  far  as  a  particular 
engine  is  concerned.  The  lead  is  greater  for  high-speed  heavy  pistons 
than  for  engines  of  the  locomotive  type,  some  marine  engines  hav- 
ing }i  inch  of  lead,  and  even  at  times  more,  according  to  the  weight 
and  speed,  while  for  high-speed  light  pistons  jV  of  ^^^^  suffices. 
It  must  be  borne  in  mind  that  the  length  of  the  connecting  rod 
materially  alters  the  chord  of  the  arc  of  supply  on  the  crank  path. 
With  a  short  rod  the  chord  becomes  longer,  and  vice  versa;  and  as 
the  versed  sine  of  the  chord  of  the  arc  of  supply  on  the  crank  path 


124  MODERN   STEAM   PRACTICE. 

must  be  a  known  quantity,  as  likewise  the  diameter  of  the  crank 
path,  when  the  opening  of  port  by  the  valve  is  determined  on,  as 
we  now  propose  to  do,  the  slide  valve  can  be  set  out  as  generally 
adapted  for  all  classes  of  engines. 

OPENING  OF  PORT  BY  VALVE. 

The  diameter  of  the  cylinder  and  speed  of  the  piston  must  also  be 
determined  on  to  find  the  opening  of  port  by  the  valve.  Sup- 
posing it  is  required  to  find  the  opening  of  port  by  the  valve,  with 
a  piston  speed  of  300  feet  per  minute  giving  out  for  a  single  cylinder 
200  nominal  horse-power,  multiply  the  constant  33,000  by  the  power 
required,  and  divide  the  product  by  the  speed  of  the  piston  per 
minute,  multiplied  by  the  constant  7  lbs.,  and  the  quotient  added 
to  half  the  area  of  the  piston-rod  will  give  the  number  of  square 
inches  of  cylinder  area ;  thus, 

■?^ooo  X  200  .0  -1 

300x7     =3142 +  28  =  3170  square  mches, 

or  say  63^  inches,  is  the  diameter  of  the  cylinder,  this  being  the 
recognized  rule  for  the  nominal  horse-power  of  marine  engines.  For 
high-pressure  engines  we  simply  take  the  steam  pressure  in  boiler 
instead  of  the  constant  7  lbs.,  making  an  allowance  of  i^  of  the 
power  required,  and  the  rule  for  finding  the  cylinder's  diameter  is 
the  same  as  for  the  marine  engine.  Thus,  supposing  the  power 
required  was  20  horse,  and  the  speed  of  the  piston  200  feet  per 
minute,  with  a  steam  pressure  of  30  lbs., 

33000  X  32  5    __  jyg.^  —  say  jc  inches  diameter. 

200  X  30  '      '  -^       -' 

To  find  the  full  area  or  opening  of  port  by  the  valve  we  will  take  the 
former  example  as  for  the  marine  engine,  namely  3170,  as  area  of 
the  cylinder  in  square  inches,  with  a  piston  speed  of  300  feet  per 
minute.  Multiply  the  cylinder  area  by  the  speed  of  the  piston  in 
feet  per  minute,  and  divide  the  product  by  the  constant  10,000,  the 
quotient  gives  the  area  of  port  by  the  valve — 

3170  X  joo  _  g-  square  inches. 

lOOOO  ''-'      ^ 

Thus  the  area  of  the  steam  port  by  the  valve,  divided  by  the 
length  of  the  steam  port,  will  give  the  opening.  The  length  of 
the  port  is  found  by  dividing  the  cylinder  diameter  by  17;  thus, 
63-5  -i-  17  =  37-5,  or  say  in  round  numbers-  38  inches,  is  the  length 


REGULATION   OF   STEAM.  125 

of  the  port;  and  again  95 -=-38  =  2-5  inches,  this  is  the  linear 
opening,  of  the  port  by  the  valve  for  a  single  port.  As  double- 
ported  valves  are  generally  adopted,  the  linear  opening  of  each  will 
be  I "25  inches. 

The  steam  ports  in  the  cylinder  are  much  in  excess  of  this,  the 
area  for  the  steam  port  being  yV  of  the  cylinder  area,  and  for  the 
central  exhaust  }i  of  the  cylinder  area  is  generally  allowed, — 

^^^-  =171  square  inches  for  the  steam  port, 
^^  =  396  square  inches  for  the  exhaust  port. 

Thus  we  would  have  for  steam  port  171 -5-38  =  4-5  for  main  steam 
port  on  cylinder,  but  as  two  are  required  the  width  of  each  will  be 
2-25  linear  inches.  As  double-ported  arrangements  have  a  bridge  or 
strengthening  piece  on  the  centre  line  of  the  steam  port,  say  i  }4  inch 
broad,  we  would  have  four  steam  ports  in  the  cylinder,  19  inches 
long  and  2^  inches  wide.  The  exhaust  or  central  port  in  the  cyHnder 
is  39^  inches  long,  and  say  10  inches  wide,  or  nearly  so,  to  give 
the  required  area,  care  being  taken  that  the  passages  into  con- 
denser are  not  contracted. 

SETTING   OUT  THE  VALVE   FACES. 


u        CVLINDEIR 

X  t)  10 

2  Fig.  68. 

inches. 

We  will  suppose  the  lap  of  the  valve  is l}i 

The  width  of  the  outer  steam  ports  on  cylinder 2^ 

The  width  of  the  outer  exhaust  port  equals  the  half  travel  of  valve. ...  3^ 

The  width  of  face  on  valve 1)4 

The  width  of  the  inner  steam  port iX 

The  lap  of  valve  for  inner  steam  port 1% 

The  width  of  inside  steam  port  on  cylinder 2^ 

The  width  of  face  on  cylinder 1}^ 

The  half  width  of  exhaust  port 5 

20^  X  2=  41  j4  inches,  is  the  length  of  the  slide  valve. 

The  face  on  the  cylinder  between  the  outer  and  inner  steam  ports 
is  found  as  follows : — 


126  MODERN   STEAM   PRACTICE. 

inches. 

The  outside  exhaust  port  on  valve 33^ 

The  width  of  the  narrow  face  on  valve I^ 

The  width  of  the  inner  steam  poft  on  valve 1% 

The  inside  lap  for  steam  port l% 

"tS 

Thus  the  valve  and  adjuncts  can  be  delineated  from  the  foregoing 
dimensions.  The  packing  ring  on  the  back  should  be  as  large  in  dia- 
meter as  the  length  of  the  ports  will  admit  of  The  rubbing  ring  on 
the  back  of  the  valve  is  of  brass,  while  the  one  the  set  screws  press 
against  is  of  wrought- iron,  a  common  gasket  packing  being  inter- 
posed between  the  rings.  Some  have  proposed  springs  along  with 
the  packing,  with  the  object  of  relieving  the  cylinder  in  case  of 
priming.  It  need  scarcely  be  stated  that  when  springs  are  intro- 
duced they  must  be  placed  so  that  the  set  screws  press  them  against 
the  wrought-iron  ring. 

RELIEVING  THE   CYLINDER   FROM   INTERNAL   PRESSURE. 

With  the  desirable  object  of  relieving  the  cylinder  from  internal 
pressure  the  author  has  arranged  a  species  of  valve  differing  mate- 
rially from  the  double-ported  class,  having  the  rings  on  the  back 
for  relieving  the  valve  from  back  pressure.  The  arrangement  pro- 
posed admits  the  steam  from  the  boiler  into  the  cylinder  through 
the  middle  port  cast  on  the  cylinder,  the  valve-casing  communicat- 
ing with  the  condenser.  The  steam  by  this  plan  has  a  tendency  to 
blow  the  valve  off  the  face,  and  to  prevent  this  occurring  the  valve  is 
provided  with  a  steel  plate  on  the  back,  let  into  and  securely  attached 
to  the  valve;  rollers  bear  on  this  plate,  fitted  with  journals  and 
guide-rods,  which  pass  through  the  back  of  the  valve-chest  cover, 
having  suitable  stuffing-boxes  perfectly  air-tight  There  are  curved 
springs  secured  with  mid  shackles  to  the  valve-casing  cover.  These 
springs  have  holes  drilled  at  the  ends,  through  which  the  spindles 
pass;  the  ends  of  the  spindles  are  screwed  and  fitted  with  nuts,  so 
that  by  adjusting  the  springs  any  amount  of  pressure  on  the  valve 
face  can  be  obtained.  It  will  be  seen  that,  from  the  steam  passing 
through  the  valve,  the  latter  is  very  nearly  in  equilibrio;  still  the 
steam  has  a  tendency  to  blow  the  valve  from  the  face.  This  is 
counteracted  by  the  rollers,  which  can  be  so  adjusted  as  to  throw 
back  a  little  more  than  the  outward  pressure ;  thus  the  only  pres- 
sure on  the  face  of  the  valve  is  the  difference  between  the  outward 


REGULATION   OF   STEAM. 


127 


pressure  of  the  steam  acting  on  the  valve  and  the  pressure  imparted 
by  the  springs,  which  can  be  adjusted  to  the  greatest  nicety.     This 


Figs.  69,  70. — Slide  Valve  by  the  Author. 

valve  requires  no  packing  rings,  and  should  priming  occur  the 
cylinders  are  instantly  relieved  from  the  water.  This  roller  motion 
should  work  easily  and  with  less  friction  than  the  arrangements 
with  packing  rings  on  the  back.  Should  the  boiler  pressure,  too, 
become  higher  than  the  working  pressure,  this  arrangement  will 
act  as  a  safety  valve,  blowing  the  steam  through  the  exhaust  into 
the  condenser  or  into  the  atmosphere,  as  with  high-pressure  engines. 


RELIEVING  THE    SLIDE   VALVE   FROM   BACK   PRESSURE. 

The  double-ported  valve  for  high-pressure  engines  differs  very 
little  from  those  for  the  marine  engine ;  in  fact,  the  only  difference 
consists  in  making  the  exhaust  ports  at  each  end  of  the  valve 
smaller,  as  likewise  the  ports  in  the  cylinder  may  also  be  reduced  in 
width,  and  when  made  very  small  no  packing  rings  are  required, 
neither  is  it  necessary  that  marine  engines  should  be  so  fitted,  as 
with  small  valves  the  pressure  is  not  much  felt.  However,  correctly 
speaking,  all  valves  should  be  relieved  from  the  back  pressure,  whether 
they  are  double-ported,  or  simply  the  original  arrangement,  with  only 


128 


MODERN   STEAM   PRACTICE. 


Fig.  71. — Equilibrium  Valve. 


three  ports  in  the  cylinder.  Some  of  these  valves  for  marine  engines 
simply  consist  of  a  frame,  having  metallic  packing  rings  bearing  on 
the  back  of  the  valve  casing  or  cover.  In  the 
valve  delineated  the  middle  recess  is  simply 
formed  to  lighten  the  casting  as  the  exhaust 
steam  passes  through  the  valve  itself  in  its 
passage  to  the  condenser.  The  packing  ring 
fits  into  a  recess  on  the  back  of  the  valve,  a 
•  plaited  gasket  is  interposed  between  the  pack- 
ing ring  and  a  thin  metallic  plate  with  springs 
for  pressing  the  valve  and  ring  to  their  respec- 
tive faces.  It  will  be  seen  that  this  valve  very 
nearly  approaches  to  what  we  may  term  an 
equilibrium  valve.  The  only  objection  to  this 
class  is  that  there  are  two  faces  to  keep  tight, 
and  that  the  ring  depends  on  its  accurate  fit, 
along  with  the  gasket  packing,  to  keep  it  steam- 
tight.  To  obviate  this  difficulty  a  variety  of 
packing  rings  have  been  devised,  depending  on 
their  metallic  contact  alone  so  as  to  make  them 
steam  tight;  and  as  it  is  an  object  in  some  engines  of  the  high- 
pressure  type,  having  great  piston  speed,  to  reduce  the  weight  of 
the  reciprocating  parts,  the  rings  have  been 
made  very  light.  An  improvem^ent  upon  the 
preceding  example  is  that  the  valve  is  fitted 
with  a  metallic  piston,  having  a  spring  ring 
fitted  to  the  piston,  the  piston  and  slide  valve 
being  pressed  to  the  faces  with  springs  inserted 
at  the  bottom  of  the  cylinder,  which  is  cast  on 
the  slide-valve.  The  exhaust,  as  in  the  pre- 
vious example,  passes  through  the  valve  into 
the  condenser;  in  such  cases  it  is  advisable  to 
fit  a  brass  face  on  the  condenser  casting,  the 
steam  chest  for  the  valve,  as  it  were,  forming 
part  of  the  condenser,  that  is,  the  valve  chest 
and  the  condenser  are  cast  all  in  one  piece. 
Another  form  has  the  piston  and  face  for  press- 
ing to  the  back  of  the  valve-casing  of  a  lighter 
section,  and  the  piston  made  steam-tight  with  steel-spring  rings 
recessed  in  the  piston.     The  piston  in  this  arrangement  is  simply 


Fig.  72. — Equilibrium  Valve. 


REGULATION   OF   STEAM. 


129 


a  ring  of  metal,  the  bearing-  surface  on  the  back  of  the  valve-casing 
being  merely  the  thickness  of  the  metal  forming  the  ring.     It  is 


y^^^^^^MSm^'^m^^NNVN^^^^ 


Fig.  73. — Equilibrium  Valve. 

held  to  the  face  on  the  valve-casing  with  two  flat  springs  placed 
inside  of  the  valve,  thus  pressing  the  valve  and  the  piston  ring 
to  their  respective  faces.  A  pin  is  inserted  in  the  valve  and  ring 
to  prevent  the  latter  turning  round;  the  valve  is  fitted  with  a  hoop 
to  which  the  valve  rod  is  attached.  This  arrangement  is  about 
as  effective  as  any.  Some  engineers  have  split  the  piston  ring; 
others  consider,  however,  that  this  is  not  required,  as  it  is  a  more 
preferable  plan  to  make  the  piston  steam-tight  with  light  steel  rings 
recessed  into  the  piston  as  already  described,  as  the  ring  of  itself 
with  a  good  fit  would  nearly  be  steam-tight,  while  the  steel  rings 
make  it  perfectly  so.  This  valve  is  admirably  suited  for  the  loco- 
motive engine;  the  rubbing  surface  on  the  packing  ring  is  very 
small,  and  there  can  be  no  doubt  that  this  is  a  benefit.  Care  must 
be  taken,  however,  to  have  ample  provision  made  for  running  off 
any  water  that  may  collect  when  the  engine  is  standing  still,  so  that 
the  narrow  rubbing  surface  may  be  kept  quite  dry.  In  the  large 
marine  compound  engines,  pi.^ton  valves  are  now  being  used. 

There  are  other  plans  for  tightening  up  the  slide-valve  rings. 
The  casing,  for  instance,  is  pro- 
vided with  a  cover  on  the  back, 
its  inside  face  being  truly  planed 
and  scraped.  To  the  valve  is 
fitted  a  ring  with  snugs  cast  on 
it,  each  snug  being  provided 
with  a  ratchet  screw  bolt  and 
spring.     This    ring    carries    two  „.  ^    ,    ,  ,  r  ^r ,    v,- 

t^        t>  fc>  pjg  y^_ — Ratchet-bolt  for  Valve  Rings. 

packing  rings,  which  are  pressed 

up  against  the  valve  chest  door  with  the  set  screws.  There  are 
holes  tapped  in  the  valve-casing  door  for  the  reception  of  screwed 
plugs.      These   holes  correspond  with  the  snugs  and   screws   for 


I30 


MODERN    STEAM    PRACTICE. 


tightening  up  the  packing  rings,  which  is  done  by  means  of  a 
box  spanner  inserted  through  the  hole,  taking  a  square  part  on 
the  screwed  studs,  which,  being  turned  in  a  particular  Avay,  causes 
the  ratchet  to  click.  Thus  the  engineer,  by  counting  the  number 
of  clicks  for  each  set  bolt,  can  set  up  the  faces  equally.  It  is 
advisable  that  the  rings  should  be  tightened  up  under  steam,  so  as 
to  adjust  the  faces  for  the  expansion  of  the  metals.  This  plan  is 
neat,  but  many  engineers  consider  it  not  nearly  so  effective  as  the 
usual  method  with  plain  set  screws,  packing  rings,  and  plaited 
gasket,  as  before  described. 

To  enter  into  details  of  an  arrangement  for  taking  the  pressure  off 
the  back  of  the  slide  valve,  with  a  piston  having  an  oscillating  link, 
&c.,  would  be  of  little  practical  benefit,  as  such  has  been  very  rarely 
adopted.  Suffice  it  to  say,  that  the  piston  works  in  a  short  pipe 
accurately  bored  out,  and  placed  or  cast  in  the  valve-casing  cover, 
having  a  link  for  connecting  the  valve;  the  steam  pressure  acting  on 
the  piston  tends  to  pull  the  slide-valve  from  the  face.  Thus  the 
force  is  suspended,  as  it  were,  on  the  link  pin,  and  consequently 
the  valve  is  more  easily  moved.  Sometimes  a  piston  has  been  intro- 
duced to  balance  the  weight  of  the  slide-valve  when  placed  verti- 
cally, and  no  doubt  the  plan  is  good  when  the  slide-valve  is  very 
large,  as  the  strain  on  the  valve  gear  is  not  so  much  felt.  The 
piston  should  be  fitted  with  small  steel  spring  rings,  thus  simplify- 
ing the  arrangement 


THE    INDICATOR    DIAGRAM. 

When  the  steam  in  the  cylinder  is  cut  off  at  any  part  of  the 
stroke  of  the  piston,  and  were  no  condensation  taking  place,  the  pres- 
sure of  the  steam  at  the  end  of  the  stroke,  or  at  any  intermediate 
portion  of  it,  could  be  calculated  to  a  nicety.  The  curved  line  that 
would  delineate  the  steam  pressure  inside  of  the  cylinder  from  the 
point  of  cut-off  would  then  be  quite  regular.  But  in  practice  there 
are  various  causes  that  tend  to  make  the  line  of  expansion  a  very 
irregular  figure;  for  instance,  with  a  slow  cut-off,  as  with  the  eccen- 
tric motion,  the  line  of  expansion  does  not  approach  so  nearly  the 


THE   INDICATOR   DIAGRAM. 


131 


theoretical  curve  as  when  the  valves  are  suddenly  shut  off  with  a 
cam  motion.  To  ascertain  the  pressure  of  the  steam  in  the  cylin- 
der, as  likewise  how  the  valve  acts  in  its  admission,  recourse  must 
be  had  to  a  very  simple  contrivance,  termed  the 
indicator,  or  miniature  cylinder  and  piston,  similar 
to  that  of  the  engine  itself  This  instrument,  in 
its  original  form,  has  a  small  cylinder,  fitted  with 
a  piston  and  rod.  On  the  top  of  the  cylinder  a 
light  spiral  steel  spring  was  placed,  fixed  to  the 
cylinder  at  one  end  and  to  the  piston  rod  at  the 
other  end,  a  p'sncil  fastened  to  the  piston  rod 
moving  along  with  it.  The  steam  pressure  raises 
the  piston  above  a  line  termed  the  atmospheric 
line,  and  when  there  is  a  vacuum  in  the  cylinder 
the  piston  is  depressed  below  the  atmospheric 
line.  Thus  the  rising  and  falling  of  the  piston 
denotes  in  the  first  instance  the  steam  pressure 
above  the  atmosphere,  and  secondly  the  vacuum 
below  it.  A  roller  is  placed  alongside,  fitted 
with  a  pulley,  having  a  cord  attached  to  it;  by 
pulling  the  cord  the  roller  rotates,  and  by  slack- 
ening the  cord  it  returns  to  its  original  position, 
being  moved  by  a  spring.  The  cord  is  fastened 
to  some  reciprocating  part  of  the  engine,  and 
by  a  reducing  lever  motion  is  imparted  to  the  A.Roiier.  ^.PuUeyandcord. 

.  f.      .  .  .  .  c.  Piston,     d.  Spindle. 

roller;  thus  the  full  stroke  of  the  piston  is  taken  e,  Pendi.  /,  piug-tap. 
in  miniature,  the  motion  being  simply  changed 
from  reciprocating  action  to  that  of  a  rotary  motion.  A  roll  of 
paper  is  fastened  round  the  roller,  and  secured  with  a  clip.  The 
pencil  fastened  to  the  piston  rod  is  made  to  press  on  the  paper 
with  a  slight  spring.  The  cord  is  moved  by  hand,  and  the  pencil 
marks  a  straight  line  on  the  paper,  termed  the  atmospheric  line. 
When  the  engine  is  in  full  working  order  this  line  never  varies  until 
the  steam  is  admitted  by  a  hand  tap  to  the  under  side  of  the 
piston,  which  instantly  rises,  distending  the  spiral  spring  accord- 
ing to  the  pressure  of  the  steam.  The  roller  being  in  motion,  a 
figure  is  traced  on  the  paper  with  the  pencil,  delineating  the  pres- 
sure on  the  piston  of  the  engine,  above  the  atmospheric  line,  as 
likewise,  on  the  return  stroke,  marking  the  vacuum  in  the  cylinder 
below  the  line,  the  spring  being  compressed  by  the  pressure  of  the 


Fig-  75- — M'Naught's 
Indicator. 


132  MODERN   STEAM   PRACTICE. 

atmosphere  acting  on  the  top  of  the  piston.  This  is  all  the  indicator 
can  give  ofif,  except  showing  at  what  part  of  the  stroke  the  steam  is 
cut  off,  and  the  behaviour  of  the  valve  in  admitting  the  steam  into  the 


Fig.  76. — Indicator  Diagram,  from  Eccentric  Valve  Motion. 

engine  cylinder.  Such  a  diagram  is  delineated :  A  B  is  the  atmos- 
pheric line,  C  denotes  the  pressure  above  it  at  the  commencement 
of  the  stroke,  D  is  the  point  of  cut-off,  E  is  the  point  where  the  steam 
in  the  cylinder  falls  to  the  atmospheric  line,  F  G  is  the  vacuum  line, 
and  G  H  is  in  compression.  The  valve  has  shut  the  opening  from 
the  condenser,  and  the  compressed  vapour  and  steam  admitted  by 
the  lead  of  the  valve  causes  the  pencil  to  rise  rapidly  to  the  point  C 
on  the  commencement  of  the  stroke.  Then  from  C  to  E  denotes  the 
steam  pressure  on  the  engine  piston,  and  from  F  to  G  the  vacuum, 
while  G  H  is  the  volume  of  cushioning  required  to  check  the  motion 
of  the  piston  at  the  end  of  the  stroke,  in  a  gradual  manner.  The 
amount  of  compression  being  greater  for  a  heavy  piston  having  a 
high  velocity  than  for  a  lighter  piston  having  the  same  velocity, 
bearing  in  mind  that  lighter  pistons  of  exceeding  high  velocity  may 
require  more  cushioning  or  opening  by  valve,  technically  termed 
"  lead,"  than  heavy  ones  moving  slowly.  It  must  be  noted  that  the 
point  D  in  the  diagram  only  approximately  shows  that  part  of  the 
stroke  where  the  steam  ports  are  entirely  shut,  or  the  communication 
from  the  boiler  cut  off  by  the  valve.  This  defect  in  the  diagram  is 
inherent  in  all  when  the  valve  is  actuated  on  by  an  eccentric,  as  the 
motion  of  the  eccentric  is  very  slow  when  shutting  the  ports,  while 
that  of  the  piston  is  rapid.  Thus,  to  a  certain  extent,  the  steam  is 
wire-drawn,  so  that  the  pressure  in  the  cylinder  is  gradually  reduced, 


THE   INDICATOR   DIAGRAM. 


133 


and  rounds  off  the  diagram,  rendering  it  difficult  to  define  the 
exact  point  of  cut-off.  To  illustrate  this  more  fully  a  diagram  is 
given  from  an  engine  fitted  with  Corlis's  valve  gear.     This  species 

of  gear  shuts  off  the  steam  from 
the  cylinder  very  quickly.  The 
steam  pressure  in  this  example  was 
50  lbs.  per  square  inch,  the  cylin- 
ders had  a  diameter  of  38  inches, 
while  the  speed  of  the  piston  was 


Fig.  77. — Indicator  Diagram,  from  Corlis's  Valve  Gear. 


500  feet  per  minute.  With  such  high  pressure  and  piston  speed 
the  diagram  approaches  more  closely  to  the  theoretical  figure  than, 
that  obtained  from  a  valve  actuated  by  the  common  eccentric. 
All  manufacturers  strive  to  obtain  a  diagram  from  their  engines  as 
near  the  theoretical  curve  as  possible,  not  that  the  engine  gives  out 
more  power  or  indicated  measure,  but  simply  that  the  valve  gear 
is  quick  and  effective.  But  as  the  power  given  off  is  rheasured  by 
the  steam  pressure  and  vacuum  as  taken  from  the  diagram,  no  one 
will  dispute  that  a  full  figure  in  the  diagram  indicates  less  power 
than  a  fine  figure ;  on  the  contrary,  more  power  must  be  developed, 
the  speed  of  piston  being  identical. 

The  indicator  diagram  is  of  great  importance  to  the  engineer,  as 
from  it  he  can  at  once  tell  the  steam  pressure  in  the  cylinder  as 
compared  with  that  in  the  boiler,  whether  to  ascertain  the  pressure 
at  the  commencement  of  the  stroke,  or  to  discover  at  what  part 
of  the  stroke  the  steam  is  cut  off, — to  notice  if  "wire-drawing" 
occurs,  or  a  sharp  cut-off,  at  what  part  of  the  stroke  the  steam 
pressure  falls  to  the  atmospheric  line,  and  whether  the  vacuum  is 
quickly  and  effectually  maintained  until  the  point  of  compression  is 
reached.  By  comparing  the  boiler  and  cylinder  pressures,  too,  he 
can  tell  what  amount  of  condensation  takes  place  in  the  pipes,  and 
adopt  means  to  prevent  it.  In  short — and  in  this  lies  the  great 
value  of  the  indicator — by  a  proper  diagram  taken  off  the  engine  he 


134 


MODERN    STEAM   PRACTICK 


can  tell  how  it  is  performing  its  duty.  By  means  of  the  indicator 
noting  the  steam  pressure  and  vacuum  acting  on  the  piston,  as  well 
as  the  velocity  of  the  piston,  at  the  time  of  trial,  a  true  estimate  of 
the  working  of  the  engine  is  obtained,  and  thus  steam  users  are 
satisfied  and  disputes  avoided. 

Some  authorities  say  Watt  invented  the  indicator,  others  assert 
that  M'Naught  successfully  introduced  it,  although  improvements 
have  since  been  made  by  others  to  suit  modern  high-speed  engines. 
The  long  stroke  of  the  piston  and  spiral  spring  causing  the  pencil 
to,  as  it  were,  "jump,"  made  the  diagram  very  irregular.  To  obviate 
this  defect  the  stroke  of  the  piston  was  reduced,  and  the  range  of 
the  pencil  multiplied  with  a  lever  parallel  motion.  Certainly  the 
improvement  is  very  effective,  and  fully  answers  the  object  in  view. 
To  suit  the  varying  steam  pressures  it  is  found  advisable  to  supply 
springs  of  different  degrees  of  power.  Thus  we  have  springs  for 
60  lbs.  to  the  inch,  and  others  1 5  lbs.  to  the  inch ;  and  it  will  thus 
be  understood  that  when  the  60  lb.  spring  is  used,  and  the  steam 

High-pressure  Cylinder. 
IS  '^  •"  " 


^tm»spft*ne  Jim' 


Steam,  45  lbs.        Vacuum,  28J^  inches. 

Indicated  horse-power,    298 '05  h.  p.  cylinder. 
Do.  do.         3io'88  L.p.        „ 


608-93 


Low-pressure  Cylinder. 

e     :?     •- 


Figs.  78,  79. — Compound  Engine  Diagrams. 


in  the  cylinders  only  15  lbs.,  that  the  steam  line  on  the  diagram 
will  only  be  ^  inch  from  the  atmospheric  line,  and  with  the  vacuum 


THE   INDICATOR   DIAGRAM.  1 35 

proportionately  less  also;  consequently  this  reduction  is  obviated  by 
using  the  1 5  lb.  spring  to  suit  the  pressure  in  the  cylinder  of  the 
engine.  For  compound  engines  varying  springs  are  necessary;  but 
•it  is  considered  that  for  ordinary  marine  engines,  and  in  all  engines 
where  the  variation  of  the  steam  pressure  is  not  great,  that  one 
scale,  and  spring  to  suit,  is  quite  sufficient,  as  a  variety  only  creates 
confusion.  To  show  this  more  fully,  take  two  diagrams  from  marine 
engines  of  the  compound  type.  The  full  figure  shows  the  behaviour 
of  the  steam  in  the  high-pressure  cylinder,  and  the  lesser  diagram 
steam  in  the  low-pressure  cylinder.  The  same  scale  is  used  for 
both  (the  diagrams  being  reduced  from  the  original).  It  will  be  seen 
that  the  diagram  for  the  low-pressure  cylinder  is  very  lean,  while 
that  for  the  high-pressure  cylinder  is  well  defined ;  and  to  make  the 
former  bolder  it  is  evident  that  a  different  spring  and  scale  must 
be  adopted.  This  would  improve  the  appearance  of  the  low-pressure 
diagram,  but  were  the  same  scale  and  spring  adopted  for  the  high- 
pressure  diagram  it  would  make  the  figure  too  large.  The  reading 
of  the  high-pressure  diagram  is  somewhat  different  from  ordinary 
high-pressure  engines.  The  diagram  in  such  cases  would  show  the 
pressure,  commencing  from  the  atmospheric  line,  while  in  the 
example  before  us  there  is  a  slight  back  pressure.  This  is  due  to 
the  steam  expanding  into  the  large  cylinder  instead  of  into  the 
atmosphere,  as  with  ordinary  high-pressure  engines. 

We  give  examples  in  which  both  the  high  and  low  pressure  cylin- 
ders have  diagrams  taken  from  them.  Both  of  the  figures  are 
well  defined,  the  scale  for  the  high-pressure  diagram  being  double 
that  for  the  low-pressure  diagram,  or  the  spring  of  double  the  power. 
Thus  it  will  be  seen  that  it  is  quite  necessary  to  have  two  sets  of 
springs  for  combined  engines,  so  that  there  may  not  be  so  great  a 
difference  in  the  diagrams,  or  that  the  figure  be  not  too  minute  in 
the  one  nor  too  bold  in  the  other.  When  the  operator  is  taking 
diagrams  off"  an  engine  he  generally  takes  them  for  both  ends  on  the 
same  paper,  provision  being  made  on  the  cylinder  for  doing  so,  the 
small  steam  pipes  fitted  being  in  communication  with  both  ends  of 
the  cylinder.  Thus  the  double  figures  are  represented,  one  for  the  top 
or  OUT  stroke,  and  another  for  the  IN  stroke  of  the  piston.  Care 
must  be  taken  that  the  area  of  the  small  pipe  connecting  both  ends 
of  the  cylinder  is  of  sufficient  size,  not  less  than  ^  inch  in  diameter, 
so  that  the  full  pressure  may  be  conveyed  instantly  to  the  piston  of 
the  indicator.   This  pipe  must  be  fitted  with  a  hand-tap  for  each  end 


136 


MODERN   STEAM    PRACTICE. 


of  the  cylinder,  so  that  when  one  of  them  is  shut  the  other  is  open  to 
the  indicator,  and  so  on  for  each  end  of  the  cyhnder.    The  examples 


High-pressure  Cjilinder. 


Steam,  54  lbs.         Vacuum,  28J^  inches 

Indicated  horse-power,     457  66  H.p.  cylinder. 
Do.  do.  71375  L.P.        „ 


Revolutions,  60. 


1171-41 


SOUOTTI  . 


Figs.  80,  81. — Compound  Engine  Diagrams. 


illustrated  are  taken  from  combined  engines  of  the  vertical  type; 
the  top  and  bottom  of  the  cylinders  are  taken  in  the  literal  sense, 
but  the  IN  stroke  of  all  engines — that  is,  when  the  crank  is  moving 
inwards  towards  the  cylinder — should  be  termed  the  IN  stroke,  and 
when  the  crank  is  moving  from  the  cylinder  the  OUT  stroke  is 
signified :  by  adhering  to  these  terms  confusion  is  prevented. 

Although  the  two  preceding  examples  show  back  pressure  on 
the  return  stroke  of  the  high-pressure  piston,  as  delineated  by  the 
diagrams,  yet  the  expansion  may  be  carried  so  far  that  the  steam 
may  fall  to  the  atmospheric  line  at  the  commencement  of  the  stroke 
of  the  large  piston  or  low-pressure  cylinder.  The  following  dia- 
grams show  that  this  has  taken  place  in  the  up  or  top  stroke  of  the 
high-pressure  piston,  the  steam  expanding  to  the  top  of  the  large 


THE   INDICATOR   DIAGRAM. 


137 


cylinder,  or  down  stroke  of  the  low-pressure  piston.      For  large 
power  this  is  an  advantage,  as  the  descent  of  the  large  piston  is 


High  and  Low  Pressure  Cylinders  combined. 


Top. 


r 

^ 

(4 

f> 

W 

25 

?> 

-ft 

Co 

'fy 

P 

V 



1  ^- 

3> 

s 

? 

S 

W 

a 

■♦                        ■«                         VI 

tC 

S 

* 

t^ 

Total  indicated  power,  1551. 
Steam,  40  lbs.        Vacuum,  28  inches.        Revolutions,  33. 


Sottom 


Figs.  82,  83. — Compound  Engine  Diagrams. 


better  balanced  than  if  great  steam  pressure  was  admitted  into  the 
cylinder.  Again,  when  the  steam  is  raising  the  small  piston,  it  will 
be  seen  that  more  steam  is  admitted,  the  cut-off  taking  place  at  a 
later  period.  The  diagram  for  the  large  cylinder  shows  steam  pres- 
sure above  the  atmospheric  line  for  a  very  short  period,  which  of 
course  is  beneficially  utilized  in  raising  the  large  piston.  These 
two  diagrams  admirably  show  the  action  of  the  slide-valve,  the 
opening  of  the  valve  being  greater  for  the  IN  stroke  than  for  the 
OUT  stroke.  This  takes  place  with  valves  having  the  same  amount 
of  cover  on  each  steam  end,  actuated  by  an  eccentric  motion. 

For  reading  off  the  steam  and  vacuum  measures  the  diagram  is 


138 


MODERN   STEAM   PRACTICE. 


divided  into  ten  parts  on  the  atmospheric  line;  the  tenth  space 
is  subdivided,  having  one-half  at  each  end,  thus  having  ten  ordinates 
as  shown ;  so  by  measuring  each  ordinate  by  the  scale  adopted,  the 
sum  of  the  ordinates  divided  by  lo  gives  the  mean  pressure  in  tJie 
cylinder.     The  power  is  run  out  by  the  usual  formula — 

Area  of  cylinder  in  square  inches  x  mean  pressure  x  speed  of  piston  in  feet  per  minute^ 
'  33000 

thus  the  real  or  indicated  power  of  the  engine  is  obtained. 

The  theoretical  line  of  expansion  of  the  steam  in  the  cylinder  is 
only  useful  to  show  how  nearly  the  diagram  as  taken  by  the  indi- 
cator approaches  it.  Without  comparing  the  theoretical  measure 
with  the  diagram  illustrated,  we  will  explain  how  the  theoretical 
line  of  expansion  is  obtained.  It  is  based  on  the  natural  law  that 
governs  pneumatics,  namely,  that  the  pressure  of  an  elastic  fluid 
varies  inversely  as  the  space  into  which  it  is  expanded  or  com- 
pressed. Thus  if  the  steam  in  the  cylinder  is  cut  off  at  one-fourth  of 
the  stroke  of  the  piston,  the  space  it  occupies  at  the  end  of  the 

stroke  will  be  four  times  the  volume  of 
the  steam  admitted  into  the  cylinder;  it 
has  expanded  into  four  times  its  bulk, 
and  the  pressure  at  the  end  of  the  stroke 
will  be  only  one-fourth  of  the  original 
volume  admitted  into  the  cylinder.  To 
find  the  pressure  of  the  steam  at  the  end 
of  the  stroke,  or  at  any  intermediate 
part  of  the  stroke  of  the  piston,  multiply 
the  number  of  inches  the  piston  has 
travelled  when  the  steam  is  cut  off  by 
the  pressure,  dividing  the  result  by  the 
total  length  of  the  stroke  in  inches,  or 
by  that  portion  of  it  that  is  required. 
Thus,  supposing  A  B  in  the  figure  repre- 
sented one-fourth  of  the  stroke,  B  being  the  point  of  cut-off,  and  the 
stroke  of  the  piston  is  36  inches,  with  a  steam  pressure  of  20  lbs.  per 
square  inch,  we  would  have — 

,^    =  5  lbs.  steam  pressure  at  the  end  of  the  stroke, 

=  6-66  lbs.  steam  pressure  at  three-quarters  of  the  stroke, 

^g-  :=  10  lbs.  steam  pressure  at  one-half  of  the  stroke. 


Fig.  84. 


Strrke 
-Iheoretical  Diagram. 


THE   INDICATOR   DIAGRAM. 


139 


Thus  there  is  one-fourth  of  the  original  pressure  at  the  end  of  the 
stroke,  at  three-fourths  of  the  stroke  one-third,  and  at  half  stroke 
one-half  of  the  original  pressure.  The  initial  pressure  will  be  20  lbs. 
cutting  off  at  one-fourth  of  the  stroke  of  the  piston,  at  one-half  it 
will  be  10  lbs.,  at  three-quarters  &66  lbs.,  and  the  terminal  pressure 
will  be  5  lbs.  The  stroke  is  delineated  by  the  horizontal  line  in  the 
figure,  and  the  vertical  line  represents  the  diameter  of  the  cylinder 
with  the  lbs.  pressure  marked  off,  the  curved  line  from  B  to  C  being 
the  theoretical  curve  of  expansion. 

The  diagram  is  taken  as  follows: — The  mechanism  attached  to 
the  engine  for  actuating  the  roller  on  which  the  paper  is  fixed  should 
be  of  the  simplest  construction.  A  plain  arm  vibrating  on  a  fixed 
pin,  having  a  slot  at  the  downward  end  so  as  to  take  a  pin  fixed 
to  the  crosshead  or  piston  rod,  for  direct-acting  engines,  is  by  far 
the  simplest  arrangement,  the  cord  being  attached  to  the  top,  a  short 
distance  from  the  vibrating  centre.  A  B  in  the  figure  represents  the 
full  stroke  of  the  piston,  and  C  D  the  reduced  stroke  for  the  diagram. 
The  cord  can  be  led  away  with  suitable  pulleys  should  the  point  of 
attachment  to  the  indicator  diverge  from  the  straight  line,  and  it  is 
convenient  to  have  a  small  pulley,  fixed 
on  a  ball-and-socket  joint,  placed  next  to 
the  indicator,  so  that  the  cord  from  the 
vibrating  lever  can  be  placed  at  different 
angles  to  that  of  the  part  interposed  be- 
tween the  pulley  and  the  roller  on  the 
indicator.  For  vibrating  cylinders,  and 
other  arrangements,  the  cord  can  be 
attached  to  the  crosshead,  and  the  motion 
reduced  with  a  large  pulley,  a  band  being 
wound  round  it,  the  length  of  the  band 
being  about  equal  to  the  stroke  of  the 
engine.  This  pulley  is  fitted  with  a  strong 
spring,  similar  to  a  watch-spring,  and  the 

strain  is  imparted  to  this  spring  instead  of  to  the  delicate  one  in  the 
instrument.  Of  course  it  is  necessary  to  have  a  smaller  pulley  on 
the  same  spindle,  so  as  to  reduce  the  stroke  for  the  diagram.  Any 
part  of  the  mechanism  of  the  engine  can,  if  corresponding  with  the 
motion  of  the  piston,  be  used  as  the  point  of  attachment  for  the 
cord,  and  simple  levers  for  reducing  the  stroke,  with  direct  means 
of  guiding  the  cord  to  the  pulley  on  the  roller  of  the  indicator,  is 


-/.— - 


\ 


\ 


Fig.  85. — Lever  for  actuating  the 
Roller  of  Indicator. 


140  MODERN   STEAM   PRACTICE. 

far  preferable  to  intermediate  pulleys  for  taking  the  motion  of  the 
reciprocating  part  to  which  the  cord  is  fixed.  The  cord  is  attached 
to  the  instrument  with  a  hook  and  running  eye;  thus  the  exact  length 
of  the  cord  is  easily  adjusted.  The  indicator  should,  if  convenient, 
be  fitted  to  each  end  of  the  cylinder,  and  a  diagram  taken  off  for 
both  ends,  without  having  a  small  pipe  in  communication  with  both 
ends  of  the  cylinder;  but  when  a  pipe  is  fitted  it  must  be  of  suffi- 
cient size,  not  less  than  ^  inch  in  diameter,  so  that  the  pressure 
may  be  the, same  for  both  ends.  If  the  pipe  is  made  too  small,  the 
friction  of  the  steam  on  the  internal  circumference  materially  tends 
to  reduce  the  pressure  on  the  small  piston  of  the  indicator.  For 
vertical  engines  the  plug-tap,  for  admitting  the  lubricant  into  the 
cylinder  for  the  lubrication  of  the  piston,  is  provided  with  a  screwed 
part  for  taking  the  indicator,  while  another  plug-tap  is  fitted  to  the 
bottom  of  the  cylinder.  These  taps  are  screwed  into  the  covers  or 
ends  of  the  cylinder.  For  horizontal  engines  they  can  be  placed  on 
and  screwed  into  the  metal  surrounding  the  steam  ports;  but  it 
is  best  when  they  are  fitted  into  the  cylinder  itself,  or  at  each  end 
on  the  covers,  or  otherwise,  as  the  rapidity  with  which  the  steam 
flows  through  the  passages  tends  to  decrease  the  pressure  acting 
on  the  indicator  piston,  although  the  actual  difference  may  be  very 
minute.  Care  must  be  taken  that  no  abrupt  bends  are  made  in  the 
small  pipe  connecting  the  top  and  bottom  of  the  cylinder  with  that 
of  the  indicator.  Of  course  there  must  be  a  small  plug-tap  fitted 
to  the  pipe,  so  that  the  communication  from  the  top  is  shut  off"  when 
the  operator  wishes  to  take  a  diagram  from  the  bottom  end  of  the 
cylinder,  and  vice  versa.  It  is  essential  that  the  indicator  should 
be  placed  v'ertically,  so  in  some  instances  large  easy  bends  on  the 
small  pipe  are  admissible,  but  in  all  cases  where  bends  are  used 
there  must  be  provision  made  for  running  off  the  water  collecting 
from  condensation. 

When  all  is  in  readiness — the  engine  going  at  its  accustomed 
number  of  revolutions,  and  all  water  in  the  cylinders  and  pipes 
ejected,  with  all  the  run-off"  valves  shut — the  operator  turns  on  the 
steam  to  the  indicator,  the  handle  for  doing  so  being  provided  with 
a  stop,  so  as  to  have  the  passage  in  the  plug-tap  full  open.  When 
the  instrument  has  made  a  few  strokes  the  cord  can  be  unhooked 
— the  diagram  has  been  taken;  and  it  is  only  necessary  to  note 
on  the  card  the  pressure  of  the  steam  in  the  boiler,  inches  of  mercury 
in,  the  gauge,  the  number  of  revolutions,  and  the  scale  adopted. 


THE  EXPANSION   OF   STEAM. 


141 


THE    EXPANSION   OF   STEAM. 

With  a  given  pressure  of  steam,  and  the  cut-off  taking  place  at 
any  part  of  the  stroke  of  the  piston,  to  find  the  mean  pressure 
exerted  on  the  piston  during  the  stroke,  by  means  of  the  following 
table  of  hyperbolic  logarithms.  Rule: — Divide  the  length  of  the 
stroke  of  the  piston  by  the  length  of  the  space  when  the  steam  is 
cut  off  from  the  cylinder;  find  in  the  table  the  logarithm  of  the 
number  nearest  to  the  quotient,  and  add  i  to  it:  the  sum  is  the  ratio 
of  the  gain.  Then  find  the  terminal  pressure  by  dividing  the  initial 
pressure  by  the  proportion  of  the  stroke  during  which  the  steam  is 
admitted  into  the  cylinder,  and  multiply  by  the  logarithm  +  i,  as 
above;  the  product  will  be  the  mean  pressure  exerted  on  the  piston. 

Example. —  Suppose  the  length  of  the  stroke  to  be  24  inches, 
initial  pressure  40  lbs.  per  square  inch,  and  the  steam  to  be  cut  off 
at  6  inches  from  the  commencement  of  the  stroke,  we  have — 

24 -=-6=:  4;  hyp.  log.  of  4  is  i"386-|-  1=2-386. 
Then  40-^-4=  10  x  2 "386  =  23-86  lbs.  mean  pressure. 

HYPERBOLIC   LOGARITHMS. 


Number. 

Logarithm. 

Number. 

Logarithm. 

Number. 

Logarithm. 

Number. 

Logarithm. 

I -05 

•048 

2*05 

•717 

3'o5 

rii5 

4-05 

1-398 

I"! 

•095 

2-1 

741 

3"i 

1-131 

4-10 

1-410 

ri5 

•139 

2-15 

765 

3-15 

I-I47 

4-15 

1-423 

1-2 

•182 

2  "2 

•788 

3*2 

1-163 

4-2 

1-435 

1-25 

•223 

2-25 

•810 

3-25 

1-178 

4-25 

1-446 

1*3 

•262 

2-3 

•832 

yi> 

i"i93 

4-3 

1-458 

1-35 

•300 

2-35 

•854 

3-35 

1-208 

4-35 

1-470 

1*4 

•336 

2-4 

•875 

3-4 

1-223 

4-4 

1-481 

1-45 

•371 

2-45 

•896 

3-45 

1-238 

4-45 

1-492 

1-5 

•405 

2-5 

•916 

3-5 

1-252 

4-5 

1-504 

i'55 

•438 

2-55 

•936 

3-55 

1-266 

4-55 

1-515 

1-6 

•470 

2-6 

•955 

3-6 

1-280 

4-6 

1-526 

1-65 

•500 

2-65 

•974 

3-65 

1-294 

4-65 

1-536 

17 

•530 

27 

*993 

37 

1-308 

4-7 

1-547 

175 

•559 

275 

roil 

375 

1-321 

475 

1-558 

1-8 

•587 

2-8 

1-029 

3-8 

I  "33  5 

4-8 

1-568 

1-85 

•615 

2-85 

ro47 

3-85 

1-348 

4-85 

1-578 

1-9 

•641 

2-9 

1-064 

3*9 

1-360 

4-9 

1-589 

1-95 

•667 

2-95 

ro8i 

3'95 

1-373 

4-95 

1-599 

2-0 

•693 

3-0 

1-098 

4-0 

1-386 

5-0 

1-609 

142 


MODERN    STEAM   PRACTICE. 
HYPERiioi.ic  Logarithms—  Continued. 


Number. 

Logarithm. 

Number. 

Logarithm. 

Number. 

Logarithm. 

Number. 

Logarithm. 

5-05 

1-619 

67 

1-902 

8-35 

2-122 

9-95 

2-297 

5'i 

1-629 

675 

1-909 

8-4 

2-128 

lo- 

2-302 

5-15 

1-638 

6-8 

1-916 

8-45 

2-134 

5-2 

1-648 

6-85 

1-924 

8-5 

2-140 

ir 

2-397 

5-25 

1-658 

6-9 

I -93 1 

12" 

2-484 

5'3 

1-667 

6-95 

1-938 

8-55 

2-145 

13- 

2-564 

5-35 

1-677 

7-0 

I  "945 

8-6 

2-151 

14' 

2-639 

5 '4 

1-686 

8-65 

2-157 

15- 

2-708 

5-45 

1-695 

7-05 

i"953 

87 

2-163 

i6- 

2-772 

5-5 

1-704 

7-1 

1-960 

8-75 

2-169 

17- 

2-833 

7-15 

1-967 

8-8 

2-174 

i8- 

2-890 

5-55 

1713 

7-2 

2-974 

8-85 

2- 1  80 

19- 

2-944 

5-6 

1-722 

7-25 

1-981 

8-9 

2-186 

20* 

2-995 

5-65 

1731 

7-3 

1-987 

8-95 

2-I9I 

57 

1-740 

7-35 

1-994 

9-0 

2-197 

24- 

3-178 

575 

1-749 

7-4 

2-OOI 

28- 

3-332 

5-8 

1757 

7-45 

2-008 

9-05 

2-202 

32- 

3-465 

5-85 

1-766 

7-5 

2-014 

9-1 

2-208 

36- 

3-583 

5"9 

1774 

9-15 

2-213 

40- 

3-688 

5-95 

1-783 

7-55 

2 -02 1 

9-2 

2-219 

44" 

3-784 

6-0 

1-791 

7-6 

2-028 

9-25 

2-224 

48- 

3-871 

7-65 

2-034 

9"3 

2-230 

52- 

3-951 

6-05 

rSoo 

71 

2-041 

9-35 

2-235 

56- 

4-025 

6-1 

I -808 

T7S 

2-047 

9-4 

2-240 

6o- 

4-094 

6-15 

i-8i6 

7-8 

2-054 

9"45 

2-246 

6-2 

1-824 

7-85 

2 -060 

9"5 

2-251 

64- 

4-158 

6-25 

1-832 

7-9 

2 -066 

68- 

4-219 

P 

1-840 

7'95 

2-073 

9'55 

2-256 

72- 

4-276 

6-35 

1-848 

8-0 

2-079 

9-6 

2-261 

76- 

4-330 

6-4 

1-856 

9-65 

2-266 

8o- 

4-382 

6-45 

1-864 

8-05 

2-085 

97 

2-272 

84- 

4-430 

6-5 

I -87 1 

8-1 

2-091 

975 

2-277 

88^ 

4-477 

8-15 

2-098 

9-8 

2-282 

92- 

4-521 

^■|5 

1-879 

8-2 

2-104 

9-85 

2-287 

96- 

4-564 

6-6 

1-887 

8-25 

2-IIO 

9'9 

2-292 

lOO' 

4-605 

6-65 

1-894 

8-3 

2-ii6 

TABLE    OF   HYPERBOLIC    LOGARITHMS, 

TO   SUIT   GIVEN    RATIOS   OF   EXPANSION. 


Portion  of  the  Stroke 

at  which  the 

Steam  is  cut  off. 

Ratio  of 
Expansion. 

Hyperbolic 
Logarithm. 

Portion  of  the  Stroke 

at  which  the 

Steam  is  cut  oft. 

Ratio  of 
Expansion. 

Hyperbolic 
Logarithm. 

1 
"ET 
2 
TT) 
1 
f 

3 

8 

1                            h 

lo- 

8^ 

5- 

4' 

3-33 

2-66 

2-5 

2* 

2^3025851 

2-0794414 

1-6094379 

1-3862943 

1-2029722 

•9783260 

•9162907 

•6931472 

6 

5 
"J 

3 

i 

r66 
1-6 

r42 

1-33 
1-25 
1-14 
I'll 

•5068176 
•4700036 
•3506568 
•2851788 
•2231435 
•1310284 
•1043600 

THE   EXPANSION   OF   STEAM.  I43 

PROPERTIES    OF    STEAM    AND    OTHER   GASES. 

Pressure,  density,  and  temperature  are  the  important  character- 
istics of  steam,  as  they  are  the  properties  which  regulate  the  econo- 
mical production  and  appHcation  of  steam  power.  Steam  as  a  gas 
is  amenable  to  the  common  laws  of  gaseous  fluids;  and,  according 
to  those  laws,  the  pressure,  the  density,  and  the  temperature  bear 
fixed  relations  to  one  another.  The  influence  of  temperature  on 
the  expansion  of  gases  under  constant  pressures  is  nearly  uniform 
for  equal  increases  of  temperature,  and  is  nearly  the  same  for 
difierent  gases.  The  expansion  of  air  may  be  assumed  to  represent 
that  of  other  gases,  and  it  is  found  by  experiment  that  air  expand.s 
:f-|-g-th  of  its  volume  at  32°  for  each  degree  of  temperature  communi- 
cated. 

The  relation  betwixt  pressure  and  volume  under  constant  tem- 
peratures is  also  sensibly  uniform  within  ordinary  limits.  For  an 
expansion  of  four  times  the  initial  volume,  experiments  on  various 
gases  show  a  corresponding  diminution  of  pressure  in  the  ratio  of 
I  to  3'99,  or  sensibly  i  to  4. 

The  total  or  constituent  heat  of  saturated  steam  is  at  all  temper- 
atures separable  into  two  parts — latent  and  sensible  heat.  The 
sensible  heat  is  that  indicated  by  the  thermometer,  and  it  varies  as 
the  pressure.  The  latent  heat  absorbed  during  the  conversion  of 
water  into  steam  constitutes  by  far  the  greater  proportion  of  the 
total  heat.  Thus  for  saturated  steam  we  have  the  following 
values : — 

Pressure.  Temperature.  Latent  Heat.  Total  Heat. 

147  lbs.         ...        212°         ...        966°-6        ...         1178^-6 
90     lbs.         ...        32o°'2     ...        89i°-4        ...         i2H°-6 

The  difference  of  total  heat  is,  in  this  case,  33°  in  favour  of  the 
higher  pressure.  It  appears,  then,  that  by  expansion  perfectly  dry 
steam  becomes  slightly  surcharged,  in  virtue  of  the  excess  of  total 
heat  due  to  higher  pressures;  and  should  it  contain  a  portion  of 
water  in  a  state  of  suspension,  a  small  part  of  this  water  must  be 
evaporated  during  expansion. 

For  steam,  and  for  gases  generally,  the  following  ratios  may  be 
adopted : — 

With  a  constant  temperature,  the  pressure  varies  simply  as  the 
density,  and  inversely  as  the  volume. 

With  a  constant  pressure,  expansion  is  uniform  under  a  uniform 


144  MODERN   STEAM   PRACTICE. 

accession  of  heat,  at  the  rate  of  ^^-g-th  of  the  volume  at  32°  for  each 
degree  of  heat.  If  then  we  add  (490°— 32°)  458°  to  the  indicated 
temperature,  the  sum  is  directly  as  the  total  volume  by  expansion, 
and  inversely  as  the  density. 

With  a  constant  vobime,  or  density,  the  increase  of  pressure  is 
uniformly  ^w^h  of  that  at  32°  for  each  degree  of  temperature 
acquired,  and  adding,  as  in  the  previous  case,  458°  to  the  indicated 
temperature,  the  sum  is  directly  as  the  total  pressure. 

Though  the  law  of  the  formation  of  saturated  steam  has  been  the 
subject  of  much  and  varied  experimenting,  it  can  as  yet  be  reached 
only  by  the  aid  of  empirical  formulas.  The  weight  of  a  cubic  foot 
of  steam  at  212°,  raised  from  water  under  the  ordinary  atmospheric 
pressure,  namely,  147  lbs.  per  square  inch,  is  '0^666  lbs.,  and  this 
is  an  expression  of  the  density  of  the  steam,  as  weight  is  a  direct 
measure  of  mass  or  quantity  of  matter.  A  cubic  foot  of  pure  water 
at  62°  weighs  62*321  lbs.;  and  the  ascertained  relative  volume  of 
saturated  steam  produced  under  the  atmospheric  pressure  is  1700 
times  that  of  the  water  at  62°  of  which  it  is  made;  therefore  ^/o^th 
of  the  weight  of  a  cubic  foot  of  this  water  expresses  the  weight  of 
an  equal  bulk  of  the  steam  so  formed,  and  it  is  in  this  way  that  the 
weight  of  steam  already  noted  was  determined.  From  these  data, 
with  the  aid  of  the  ratios  already  established,  the  relations  of  pres- 
sure, volume,  and  temperature  may  be  found. 

To  find  the  relative  volume  of  steam. — Add  458  to  the  temper- 
ature; divide  the  sum  so  found  by  the  total  pressure,  and  multiply 
by  37'3-     The  product  is  the  relative  volume. 

To  find  the  total  pressure  of  steam. — Add  458  to  the  tempera- 
ture; divide  the  sum  by  the  relative  volume,  and  multiply  by  37'3. 
The  product  is  the  total  pressure. 

To  find  the  temperature  of  steam, — Multiply  the  total  pressure 
by  the  relative  volume,  and  divide  by  37"3;  from  the  quotient  sub- 
tract 458.     The  remainder  is  the  temperature. 

To  find  the  weight  of  steam. — Divide  62*32 1  by  the  relative 
volume;  the  quotient  is  the  weight  per  cubic  foot. 

Motion  of  Steam. — It  is  well  understood  that  steam  unimpeded 
moves  with  great  velocity  from  one  locality  to  another,  under 
slight  differences  of  pressure.  Steam  may  flow  into  a  vacuum,  or 
it  may  deliver  itself  into  the  atmosphere,  or,  further,  it  may  flow 
into  steam  of  less  density.  The  conditions  of  its  flow  in  the  first 
and  in  the  other  cases  are  different;   as  in  the  second  case,  for 


THE  EXPANSION   OF   STEAM.  I45 

example,  147  lbs.,  or  approximately  15  lbs.,  of  its  total  pressure  go 
for  nothing  in  counteracting  the  atmospheric  resistance,  before  the 
slightest  motion  is  possible.  Thus,  in  the  second  case,  at  all  pres- 
sures the  motion  of  the  steam  is  due  solely  to  the  difference  of  its 
inherent  pressure  and  that  of  the  atmosphere.  The  ordinary 
method  of  estimating  the  velocity  of  the  flow  of  gases  or  liquids 
under  pressure  is  founded  on  the  laws  of  falling  bodies;  it  is  a  very 
beautiful  application  of  the  law  of  gravitation,  and  it  yields  results 
simply  and  directly.  A  quantity  of  steam  confined  in  a  boiler,  of 
a  given  pressure  and  known  density,  would  flow  into  a  vacuum 
through  an  opening  from  the  boiler  with  a  certain  initial  velocity, 
and  this  velocity  would  be  the  same  as  that  which  would  be  given 
to  a  liquid  of  the  same  weight  as  the  steam,  flowing  out  under  the 
same  pressure.  The  velocity  of  efflux  referred  to,  when  unretarded 
by  physical  obstructions,  is  precisely  that  which  the  liquid  would 
acquire  in  falling  through  the  height  of  a  column  of  the  same  liquid 
I  inch  square,  equal  in  weight  to  the  pressure  of  the  steam  per 
square  inch.  By  the  laws  of  falling  bodies  it  is  known  that  the 
velocity,  v,  acquired  in  falling  freely  through  any  height,  h,  is  equal 
to  eight  times  the  square  root  of  the  height,  or  v=.'i\lh.  Thus  the 
velocity  of  efflux  into  a  vacuum  is  determinable,  and  the  following 
is  the  method  of  finding  it : — 

Given,  the  total  pressure  of  the  steam,  which  we  suppose  to  be 
saturated,  as  in  all  ordinary  cases  it  is;  divide  the  pressure  per  square 
inch  by  the  weight  of  a  cubic  foot  of  the  steam;  the  quotient  is  the 
height  of  a  uniform  column  of  steam  i  foot  square,  equal  in  weight 
to  the  pressure  of  the  steam  per  square  inch.  Multiply  the  quotient 
as  found  by  144,  the  number  of  square  inches  in  a  square  foot  of 
base,  and  the  product  is  the  height  of  a  i-inch  column  of  the  steam, 
equal  in  weight  to  the  given  pressure  of  that  steam  on  the  square 
inch. 

To  find  the  velocity  with  which  saturated  steam,  flows  freely  into 
a  vacuum. — Divide  the  total  pressure  per  square  inch  in  lbs.  by  the 
weight  of  a  cubic  foot  of  the  steam  in  lbs.,  and  find  the  square  root 
of  the  quotient;  multiply  this  result  by  96.  The  product  is  the 
required  velocity  in  feet  per  minute. 

To  find  the  velocity  with  ivhicJi  saturated  steam  freely  flows  into 
the  atmosphere,  or  into  steam  of  inferior  pressure. — Take  the  differ- 
ence of  pressures  of  the  two  steams  for  the  effective  pressure,  divide 

the  effective  pressure  in  lbs.  per  square  inch  by  the  weight  of  a  cubic 

10 


146  MODERN    STEAM    PRACTICE. 

foot  of  the  denser  steam  in  lbs.,  and  multiply  the  square  root  of  the 
quotient  by  96.  The  product  is  the  required  velocity  in  feet  per 
second. 

To  find  the  pressure  to  which  saturated  steam  is  reduced  when  it 
flows  freely,  with  a  given  velocity,  from  one  vessel  into  another. — 
Multiply  the  square  of  the  velocity  in  feet  per  second  by  the  weight 
in  lbs.  of  a  cubic  foot  of  steam  of  the  initial  total  pressure,  and  divide 
the  product  by  9216.  The  quotient  thus  found  expresses  the  differ- 
ence of  the  initial  and  final  pressures;  subtract  this  quotient  from 
the  given  initial  pressure,  and  the  remainder  is  the  reduced  total 
pressure  sought. 

Of  the  loss  of  pressure  generally  wJiich  accompanies  the  movements 
of  steajn. — It  has  been  seen  that  a  reduction  of  pressure,  great  or 
small,  necessarily  accompanies  even  the  free  motion  of  steam,  the 
difference  being  consumed  in  communicating  that  motion.  By  far 
the  heaviest  losses  are,  however,  due  to  the  resistances  of  bends  and 
surface  friction  of  pipes,  8z:c.  It  has  been  found  from  experiment  on 
stationary  engines  and  boilers  that  the  losses  on  various  accounts 
follow  these  general  ratios. 

The  difference  of  pressures  in  the  boiler  and  cylinder  is — 

1st.  As  the  density  of  the  steam,  and  as  the  square  of  the  speed 
of  piston. 

2d.  As  the  square  of  the  ratio  of  area  of  piston  to  cross  section  of 
steam  pipe. 

3d.  As  a  factor  dependent  on  bends  and  friction. 

The  permanent  difference  of  pressure  caused  by  passing  through 
a  stricture  in  a  pipe,  otherwise  of  uniform  diameter  before  and 
behind  the  stricture,  is  as  the  density  of  the  steam,  and  as  the 
square  of  the  difference  of  speeds  through  the  larger  and  smaller 
parts  of  the  pipe. 

The  friction  of  a  fluid  through  a  pipe  appears  to  vary  more  or 
less — 

1st.  As  the  length  directly. 

2d.  As  the  diameter  inversely. 

3d.  As  the  square  of  the  velocity  directly, 

4th.  As  the  density  directly. 


THE   EXPANSION   OF   STEAM. 


147 


PROPERTIES    OF    SATURATED    STEAM   AT   DIFFERENT 
PRESSURES. 


Pressure  in 

lbs.  per 
square  inch 

Temperature 

Total  Heat 

Cubic  inches 

of  water  to 

produce 

Volume  of  Steam  produced 
by  I  of  water. 

Weight  of 
I  cubic  foot 

above  the 
pressure 

in  degrees  of 
Fahrenheit. 

in  degrees  of 
Fahrenheit. 

I  cubic  foot 
of  Steam, 

of  Steam 
in  lbs. 

of  the 

according  to 

Pambour. 

Other 

atmosphere. 

Pambour. 

Authorities. 

I 

2l6'3 

II 79-9 

1-09 

1572 

I515 

•0397 

2 

219-5 

I  1 80-9 

I-16 

1487 

I43I 

•0419 

\3 

222-5 

ii8r8 

1*22 

I4IO 

1357 

•0442 

4 

225-4 

1182-7 

1-28 

1342 

1290 

•0465 

5 

228-0 

1 183-5 

1-35 

1280 

1229 

•0487 

6 

230-6 

1 184-3 

1-41 

1224 

I  174 

•0510 

7 

233'! 

1 185-0 

1-47 

II72 

II23 

•0532 

8 

235'5 

1185-7 

1-53 

II25 

1075 

•0554 

9 

237'9 

1186-5 

1-59 

1082 

1036 

•0576 

lO 

240-2 

1187-2 

1-65 

1042 

996 

•0598 

II 

242-3 

1 187-9 

1-71 

1005 

958 

*0620 

12 

244-4 

1188-5 

1-77 

971 

926 

•0642 

13 

246-4  . 

1189-1 

1-84 

939 

895 

•0664 

14 

248-4 

1 189-7 

1-91 

909 

866 

•0686 

15 

250-4 

1190-3 

1-95 

881 

838 

•0707 

16 

252-2 

1190-8 

2*02 

855 

813 

•0729 

17 

254-1 

1191-4 

2-07 

830 

789 

■0751 

18 

255*9 

1 192-0 

2-13 

807 

767 

*o772 

19 

257-6 

1192-5 

2-19 

785 

746 

•0794 

20 

259*3 

1 193-0 

2-25 

765 

726 

•0815 

21 

260*9 

ii93"5 

2-31 

745 

707 

•0837 

22 

262-6 

1194-0 

2-37 

727 

688 

•0858 

23 

264-2 

1194-5 

2-43 

709 

671 

•0879 

24 

265-8 

1 195-0 

2*49 

693 

655 

'0900 

25 

267-3 

1195-4 

2-55 

677 

640 

•0921 

26 

268-7 

1 195-9 

2-6i 

661 

625 

•0942 

27 

270-2 

1 196-3 

2-67 

647 

611 

•0963 

28 

271-6 

1196-8 

2-72 

634 

598 

•0983 

29 

273-0 

1 197-2 

2*78 

621 

585 

•1004 

30 

274-4 

1 197-6 

2-84 

608 

572 

•1025 

31 

275-8 

1 198-0 

2-89 

595 

561 

•1046 

32 

277-1 

1 198-4 

2-95 

584 

550 

•1067 

33 

278-4 

1198-8 

3-01 

573 

539 

•1087 

34 

279-7 

1 199-2 

3-07 

562 

529 

•I  108 

35 

281-0 

1 199-6 

3-13 

552 

518 

•I  129 

36 

282-3 

1 200-0 

3-i8 

542 

509 

•1150 

37 

283-5 

1 200-4 

3-24 

532 

500 

•1171 

38 

284-7 

I200-8 

3-30 

523 

491 

•I  192 

39 

285-9 

I20I-I 

3-36 

514 

482 

•1212 

40 

287-1 

1201*5 

3-41 

506 

474 

•1232 

41 

288-2 

1 201 -8 

3'46 

498 

466 

•1252 

42 

289-3 

1202*2 

3-52 

490 

458 

•1272 

43 

290-4 

I202*5 

3-58 

482 

451 

•1292 

44 

291-6 

1202-9 

3-64 

474 

444 

•I3H 

45 

292-7 

1203*2 

3'7o 

467 

437 

•1335 

148 


MODERN   STEAM   PRACTICE. 
Properties  of  Saturated  Steam — Continued. 


Pressure  in 

Cubic  inches 

lbs.  per 

of  water  to 

Volume  of  Steam  produced 

square  inch 

Temperature 

Total  Heat 

produce 

by  I  of  water. 

Weight  of 
1  cubic  foot 

above  the 

in  degrees  of 

in  degrees  of 

I  cubic  foot 

of  Steam 

pressure 

Fahrenheit. 

Fahrenheit. 

of  Steam, 

in  lbs. 

of  the 

according  to 

Pambour, 

Other 

atmosphere. 

Parnbuur. 

Authorities. 

46 

293-8 

1203-6 

3-75 

460 

430 

•1356 

47 

294-8 

1203-9 

3-81 

453 

424 

•1376 

48 

295-9 

1204-2 

3-86 

447 

417 

•1396 

49 

296-9 

1204-5 

3-92 

440 

411 

•1416 

50 

298-0 

1204-8 

3-98 

434 

405 

•1436 

51 

299-0 

I205-I 

4-03 

428 

399 

•1456 

52 

300-0 

1205-4 

4-09 

422 

393 

•1477 

53 

300-9 

1205-7 

4-14 

417 

388 

•1497 

54 

301-9 

1206-0 

4-20 

411 

383 

•I516 

55 

302-9 

1206-3 

4-25 

406 

378 

•1535 

56 

303-9 

1206-6 

4-30 

401 

373 

•1555 

57 

304-8 

1206-9 

4-36 

396 

368 

•1574 

58 

305-7 

1207-2 

4-41 

^21 

363 

•1595 

59 

306-6 

1207-5 

4-47 

386 

359 

•1616 

60 

307-5 

1207-8 

4-53 

381 

353 

•1636 

61 

308-4 

i2o8-o 

4-58 

377 

349 

•1656 

62 

309-3 

1208-3 

4-64 

372 

345 

•1675 

63 

310-2 

1208-6 

4-69 

368 

341 

•1696 

64 

311-1 

1208-9 

4-74 

364 

337 

■I716 

65 

312-0 

1 209- 1 

4-81 

359 

333 

•1736 

66 

312-8 

1209-4 

4-86 

355 

329 

•1756 

67 

313-6 

1209-7 

4-92 

351 

325 

•1776 

68 

314-5 

1209-9 

4-96 

348 

321 

•1795 

69 

315-3 

I2IO-I 

5-02 

344 

318 

-1814 

70 

316-1 

1210-4 

5-08 

340 

314 

•1833 

71 

316-9 

I2IO-7 

5-12 

337 

311 

•1S52 

72 

317-8 

I2IO9 

5-18 

333 

308 

•187I 

73 

318-6 

i2iri 

5-23 

330 

305 

-189I 

74 

319-4 

1211-4 

5-30 

326 

301 

'I9IO 

75 

320-2 

1 2  I  I  -6 

5-43 

323 

298 

•1929 

76 

321-0 

1211-8 

5-40 

320 

295 

•1950 

77 

321-7 

I2I2-0 

5-45 

317 

292 

-1970 

78 

322-5 

I212-3 

5-52 

3^3 

289 

-1990 

79 

323-3 

I212-5 

5-57 

310 

286 

•2010 

80 

324-1 

I2I2-8 

5-62 

307 

283 

•2030 

81 

324-8 

121  3-0 

5-66 

305 

281 

•2050 

82 

325-6 

1213-3 

5-72 

302 

278 

•2070 

83 

326-3 

I213-5 

5-77 

299 

275 

•20S9 

84 

327-1 

I213-7 

5-83 

296 

272 

■2108 

85 

327-8 

I2I3-9 

5-89 

293 

270 

•2127 

86 

328-5 

I214-2 

5-95 

290 

267 

•2149 

87 

329-1       . 

I2I4-4 

6-00 

288 

265 

•2167 

88 

329-9 

I2I4-6 

6-o6 

285 

262 

•2184 

89 

330-6 

1214-8 

6-IO 

283 

260 

•2201 

90 

331-3 

I215-O 

6-14 

281 

257 

•2218 

91 

331-9 

I215-2 

6-21 

278 

255 

•2230 

92 

332-6 

1215-4 

6-26 

276 

253 

•2258 

THE   EXPANSION   OF   STEAM. 


149 


Properties  of  Saturated  Steam — Cotttinued. 


Pressure  in 

lbs.  per 
square  inch 

Temperature 

Total  Heat 

Cubic  inches 

of  water  to 

produce 

Volume  of  Steam  produced 
by  I  of  water. 

Weight  of 
I  cubic  foot 

above  the 

in  degrees  of 

in  degrees  of 

I  cubic  foot 

of  Stea.ni 

pressure 

Fahrenheit. 

Fahrenheit. 

of  Steam, 

of  the 

according  to 

Pambour 

Other 

' 

atmosphere. 

Pambour. 

Authorities. 

93 

333'3 

1215-6 

6-32 

273 

251 

•2278 

94 

334-0 

I215-8 

6-37 

271 

249 

•2298 

95 

334-6 

i2i6-o 

6-42 

269 

247 

•2317 

96 

335-3 

I2I6-2 

6-47 

267 

245 

•2334 

97 

336-0 

1216-4 

6-52 

265 

243 

•2351 

98 

336-7 

i2i6-6 

6-57 

263 

241 

•2370 

99 

337-4 

I2I6-8 

6-62 

261 

239 

•2388 

100 

338-0 

1217-0 

6-67 

259 

237 

•2406 

lOI 

338-6 

1217-2 

6-72 

257 

235 

•2426 

102 

339-3 

1217-4 

6-77 

255 

233 

•2446 

103 

339-9 

1217-6 

6-82 

253 

231 

•2465 

104 

340-5 

1217-8 

6-88 

251 

229 

•2484 

105 

341-1 

i2i8-o 

6-93 

249 

227 

•2503  ' 

106 

341-8 

I2l8-2 

.     6-99 

247 

225 

•2524 

107 

342-4 

1218-4 

7-04 

245 

224 

•2545 

108 

343-0 

I218-6 

7-II 

243 

222 

•2566 

109 

343-6 

I218-7 

7-17 

241 

221 

•2587 

IIO 

344-2 

I218-9 

7-23 

239 

219 

•2608 

III 

344-8 

1219-1 

7-26 

238 

217 

•2626 

112 

345-4 

1219-3 

7-32 

236 

215 

•2644 

113 

346-0 

I2I9-4 

7-38 

234 

214 

•2662 

114 

346-6 

1219-6 

7-45 

232 

212 

•2680 

115 

347-2 

I219-8 

7-48 

231 

211 

•2698 

117 

348-3 

1220-2 

7-57 

228 

208 

•2735 

119 

349-5 

I220-6 

7-68 

225 

205 

•2771 

121 

350-6 

1220-9 

TJ2> 

222 

202 

•2807 

123 

351-8 

1221-2 

7-84 

219 

199 

•2846 

125 

352-9 

1221-5 

8-0 

216 

197 

•2885 

127 

354-0 

1221-9 

8-II 

213 

194 

•2922 

129 

355-0 

1222-2 

8-22 

210 

192 

•2959 

131 

356-1 

1222*5 

8-3 

208 

189 

•2996 

133 

357'2 

1222-9 

8-42 

205 

187 

•3033 

135 

358-3 

1223-2 

8-51 

203 

184 

•3070 

145 

363-4 

1224-8 

9-04 

191 

174 

•3263 

'^5 

368-2 

I225-I 

9-54 

181 

164 

•3443 

165 

372-9 

1227-7 

10-04 

172 

155 

•3623 

175 

377-5 

1229-1 

10-53 

164 

148 

•3800 

185 

381-7 

1230-3 

11 'O 

157 

141 

•3970 

Mole. — According  to  Rankine  and  others,  the  relative  volume  of  steam  is  less  than  has 
been  commonly  assigned  to  it  by  Pambour,  following  the  laws  already  explained;  Pam- 
bour having  treated  steam  as  a  permanent  gas,  instead  of  as  being,  what  it  is  in  actual 
practice,  highly  saturated. 


STATIONARY   ENGINES. 


PUMPING   ENGINES    FOR   MINES. 
One  of  the  earliest  and  still  a  principal  use  of  the  steam-engine 


Fig.  86. — Cornish  Engine. 

is  for  pumping  the  water  out  of  the  mines  from  which  we  obtain 


STATIONARY   ENGINES. 


iSi 


our  coal,  ironstone,  and  other  ores.  There  would  be  great  difficulty 
in  reaching  those  vast  stores  of  hidden  treasure  without  the  power- 
ful aid  of  the  steam-engine,  which  enables  us  to  overcome  many  of 
the  risks  and  difficulties  encountered  in  mining  operations. 

The  single-acting  beam  engine  is  generally  adopted  for  pumping 
the  water  from  great  depths.  These  great  beams  of  cast-iron — 
and  in  some  cases  of  wrought-iron  plates,  stiffened  with  angle  or 
T-iron — are  supported  by  pillow  blocks,  resting  on  a  wall  of  masonry 
carried  up  to  a  convenient  height  above  the  top  of  the  cylinder. 
The  beam  is  in  two  halves,  with  gudgeons  between  them,  and  is 
connected  to  the  piston-rod  of  the  steam  cylinder  by  a  crosshead 


^^ 


Fig.  87. — Crosshead  and  Side-links  of  Parallel  Motion  for  Piston-rod  of  Cornish  Engine. 

A,  Crosshead.     b.  Piston  rod.     c.  Loose  collar.     D,  Key.     E,  Links.     F,  Beam  gudgeon. 
G,  Bearings  for  parallel  bars. 

and  parallel  motion;  and  in  some  instances  the  crosshead  of  the 
piston-rod  works  in  suitable  cast-iron  guides,  and  is  connected  to 
the  beam  gudgeons  by  plain  links.  This  motion  is  not  so  expen- 
sive in  first  cost,  and  the  wear  and  tear  is  greatly  reduced. 

The  cylinder  A  is  a  plain  casting  with  port  c  cast  on  at  the  top, 
incased  in  an  outer  cylinder  B,  to  which  it  is  bolted,  flanges  being 
cast  on  each  at  the  top  for  that  purpose.  The  outer  casing  or 
cylinder  is  bolted  to  a  separate  bed-plate  D  at  the  bottom.  A  space 
is  left  between  the  two  cylinders  for  the  admission  of  steam  from 
the  boiler;  and  they  are  made  steam-tight  at  the  bottom,  raised  strips 


152 


MODERN    STEAM    PRACTICE. 


being  cast  on  each,  and  turned  slightly  conical.     A  small  branch 
pipe  is  cast  on  the  outer  casing  at  the  top  for  the  admission  of  the 

steam,  which  forms  a  steam-jacket 
around  the  internal  cylinder,  and 
one  at  the  bottom  to  run  off  the 
water  from  the  condensation  of 
the  steam  in  the  annular  space 
between  the  two  cylinders;  each 
of  these  pipes  is  fitted  with  a  plug 
tap.  The  bed-plate  D  is  a  strong 
casting,  with  port  E  cast  on,  and  is 
bolted  down  through  the  founda- 
tions with  six  holding-down  bolts. 
There  is  a  bottom  plate  F  fitted 
into  and  made  tight  by  a  rust  joint. 
The  cylinder  cover  G  is  an  open 
casting,  with  separate  covering 
plate  H,  and  has  the  stufifing-box  I 
cast  on,  which  is  fitted  with  the 
usual  lantern  brass  K,  and  gland  L, 
for  the  packing  of  the  piston  rod. 
The  piston  M  is  also  an  open  cast- 
ing, ribbed  at  the  under  side,  and 
fitted  with  a  junk  ring  N,  having 
bolts  with  nuts  recessed  in  the 
body  of  the  piston;  there  are  two 
spring  packing  rings  o,  of  cast  iron, 
accurately  turned  and  made  per- 
fectly steam-tight.  The  piston  rod 
is  let  in  through  the  under  side, 
and  is  turned  conical,  fitting  into 
a  corresponding  hole  in  the  piston, 
the  rod  being  secured  with  a  cot- 
ter P  at  the  top.  The  cylinder  is 
fitted  with  a  ring  Q  of  wood  at  the  bottom,  to  deaden  the  shock 
should  the  piston  descend  so  far. 

The  pump  rods  are  directly  attached  to  the  gudgeon  at  the  other 
end  of  the  beam  by  suitable  wrought-iron  straps,  jib,  and  key.  The 
end  of  the  pump  rod  is  covered  by  plates  on  each  side,  fastened  by 
cross  bolts  passing  through  and  through,  to  prevent  the  wood  strip- 


. — Cylinder,  Piston,  &c. 


STATIONARY   ENGINES. 


153 


ping.     The  pump  rods  of  timber  bend  to  the  versed  sine  described, 
but  being  of  great  length  the  motion  is  but  little  felt. 

The  pumps  are  of  two  kinds — lifting  or  bucket  pumps  and  for- 


9 


Fig.  89. — Pump  Rod  of  Cornish  Engine. 

A,  Wooden  rod.     B  B,  Wrought-iron 
straps,  with  jib  and  cotter,     c,  Side  plates. 
p,  Beam  gudgeon. 


Fig.  90. — Lifting  Set.     Bucket,  18  inches  in  diameter. 

A,  Suction  pipe.       B,  Suction-valve  chest. 

C  Working  barrel.       D,  Delivery-valve  chest. 

E,  Wrought-iron  strap  shrunk  on. 


cing  or  plunger  pumps;  and  in  some  instances  a  combination  of  the 
solid  bucket  and  plunger  pump  is  adopted. 

In  the  former  of  these,  as  indeed  in  all  pumps,  the  water  is  forced 
up  the  pipe  by  the  pressure  of  the  atmosphere,  when  a  few 
strokes  of  the  pump  bucket  have  caused  a  partial  vacuum  in  the 
pump  barrel.     The  suction  valve  should  be  placed  somewhat  less 


154 


MODERN   STEAM   PRACTICE. 


than  30  feet  from  the  surface  of  the  water  in  the  shaft  or  pit  to  be 
drained,  28  feet  being  a  convenient  height;  that  is  to  say,  when  the 
water  passes  through  the  valve  to  the  top  of  a  soHd  bucket.  But 
when  a  hollow  bucket  is  adopted,  with  the  discharge  valve  fitted 
thereto,  the  distance  from  the  level  of  the  water  to  the  height  to 
which  the  bucket  ascends  in  the  pump  barrel  should  not  exceed 
28  feet;  consequently  the  suction 
valve  in  the  pipe  will  be  lower  down. 
In  the  former  of  these  arrangements 
the  water  is  drawn  through  the  suc- 
tion valve  on  the  down  stroke  of  the 
solid  bucket,  and  in  the  up  stroke 
the  suction  valve  closes,  and  the 
water  is  discharged  through  a  valve 
placed  in  the  stand  pipe  above  the 
suction  valve,  until  the  return,  or 
down  stroke  of  the  bucket,  when  the 
discharge  valve  closes  simply  by 
the  weight   of  water   upon  it;    the 


Fig.  91. — Forcing  Set.     Plunger  i8  inches  in  diameter,  arranged  with  one  door  for  each  valve. 

A,  Suction  pipe,     b,  Suction-valve  seating,     c,  Delivery- valve  seating.     D,  Plunger.     E,  Air  valve. 
F,  Stand  pipe.     G,  Stuffing-box  piece  and  gland. 


suction  valve  then  opens,  and  the  pump  barrel  is  filled  as  before; 
and  so  on.  With  the  hollow  bucket  the  water  is  drawn  through  the 
suction  valve  in  like  manner,  but  with  this  difference,  that  the 


STATIONARY   ENGINES. 


155 


bucket  is  ascending,  consequently  it  is  discharging  and  drawing  the 
water  into  the  pump  barrel  at  the  same  time,  and  the  down  stroke 
of  the  bucket  simply  allows  the  water  above  the  suction  valve  to 
pass  through  the  valve  fitted  to  the  bucket,  to  be  again  discharged 
as  already  explained. 

The  force  or  plunger  pump  is  just  a  vertical  arrangement  of  that 
type  universally  used  as 
feed  pumps  for  all  classes 
of  engines,  the  upward 
stroke  of  the  plunger,  after 
the  vacuum  is  fully  esta- 
blished in  the  pump  barrel, 
drawing  the  water  through 
the  bottom  valve,  and  dis- 
charging it  through  the  top  ^ 
valve  fitted  to  the  stand 
pipe.  The  height  to  which 
the  bottom  of  the  plunger 
ascends  should  not  exceed 
28  feet,  as  in  the  previous 
example;  and  the  suction 
and  discharge  valves  should 
be  arranged  below  that 
height.  It  is  evident  that 
this  pump  will  discharge  a 
column  of  water  equal  to 
the  area  of  the  plunger  and 
length  of  its  stroke,  as  in- 
deed do  all  pumps,  whether 
they  are  lifting  or  forcing 
sets.  It  is  found  advisable, 
however,  to  fit  a  small  valve 
opening  outwards,  so  as  to 
discharge  the  air  collecting 
at  the  top  of  the  barrel, 
and  consequently  a  little 
water  is  ejected  at  each 
stroke.  The  plunger  is  a  plain  cylinder  turned  all  over,  and  secured 
directly  to  the  wooden  pump  rod;  the  rod  is  turned,  and  then 
driven  tightly  in  and  wedged  with  iron  wedges  at  the  ends,  a  collar 


Fig.  92.  —  Forcing  Set.     Plunger  23^^  inches  in  diameter, 
arranged  wibh  one  door  for  both  valves. 

A,  Suction  pipe,  b,  Snction-valve  seating,  c.  Delivery-valve 
seating.  D,  Phinger.  E,  Branch  from  air  valve.  F,  Stand 
pipe.     G,  Stuffing-box  piece  and  gland. 


156 


MODERN   STEAM   PRACTICE. 


being  left  at  the  top.  All  the  flanges  of  the  pump  fittings  should 
be  bracketed,  and  the  valve -chest  doors  strongly  ribbed  in  the 
casting,  and  secured  with  deep  nuts,  the  hoop  bolts  passing  round 
the  valve  chest,  the  flanges  having  strong  wrought-iron  hoops  shrunk 
on.  The  arrangements  shown  are  very  compact;  the  bottom 
of  the  pump  resting  on  the  cistern  placed  high  up  above  the  lifting 
set,  the  suction  pipe  of  the  latter  (Fig.  90)  being  as  long  as  possible 
in  order  to  make  provision  for  inspecting  the  valves  in  the  event  of 

the  water  accumulating  or  rising  at 
the  bottom  of  the  shaft;  the  valves 
also  are  so  arranged  that  in  the 
event  of  the  water  rising  above  the 
doors  they  can  be  drawn  out  from 
the  surface  for  inspection,  and  again 
placed  in. 

In  the  combination  of  the  solid 
plunger  and  bucket  pump  the  water 
delivery  is  equalized;  the  barrel  is 
accurately  bored  out,  and  fitted 
with  a  gland  at  the  top  for  the 
plunger  to  pass  through,  making  it 
perfectly  air  and  water  tight.  The 
area  of  the  plunger  is  exactly  one- 
half  of  the  area  of  the  pump  barrel, 
consequently  at  the  down  stroke, 
the  barrel  being  full  of  water,  it  is 
forced  through  the  valve  in  the 
bucket ;  and  the  water  being  forced 
into  one-half  of  the  space,  one-half 
of  the  contents  of  the  pump  is  dis- 
charged in  the  down  stroke  and 
one -half  in  the  up  stroke.  The 
plunger  in  this  arrangement  can  be 
made  to  act  as  an  air  vessel,  thus 
the  flow  of  the  water  is  very  regu- 
lar, and  the  shock  of  the  valves  be- 
comes somewhat  easier.  This  pump 
can  be  arranged  with  a  solid  piston, 
having  suction  and  delivery  valves  as  in  ordinary  pumps.  There 
must,  however,  be  a  passage  in  connection  with  the  top  of  the  barrel 


Fig.  93. — Combined  Plunger  and  Bucket  Pump. 

A,  Suction  pipe.       B,  Clack  or  suction  valve. 

C,  Bucket.     D,  Plunger.     E,  Stand  pipe. 

F,  Stuffing-piece  box  and  gland. 


STATIONARY  ENGINES.  15/ 

of  the  pump  and  the  discharge  pipe,  and  in  this  way  the  water  at 
the  down  stroke  of  the  piston,  being  forced  through  the  discharge 
valve,  one-half  flows  above  the  piston  and  the  other  half  is  dis- 
charged up  the  stand  pipe;  until  the  up  stroke  takes  place,  when 
the  other  half  is  also  discharged.  Thus  in  the  up  stroke  the  piston 
is  drawing  the  water  up  the  suction  pipe,  filling  the  pump  barrel 
and  discharging  one-half  of  its  cubical  contents  at  one  and  the  same 
time ;  while  during  the  down  stroke  the  water  is  forced  out  of  the 
barrel,  one-half  of  it  fills  the  vacuity  above  the  piston  and  the  other 
half  is  discharged.  It  will  thus  be  seen  that  a  smaller  stand  pipe 
will  suffice  for  this  class  of  pump;  and  where  the  flow  of  water  from 
the  pump  requires  to  be  uniform,  this  arrangement  has  a  decided 
advantage  over  the  foregoing  examples.  At  the  bottom  of  the  air 
pipe  a  suction  piece  is  fitted,  having  a  number  of  holes  of  about 
I  inch  in  diameter,  to  prevent  extraneous  matter  lodging  in  the 
pump  and  destroying  the  proper  action  of  the  valves.  All  classes 
of  pumps  are  so  fitted,  and  lifting  sets  have  in  some  cases  a  foot 
valve  placed  at  the  bottom  of  the  air  or  suction  pipe. 

In  connection  with  the  stand  pipe  and  suction  pipe  in  lifting 
arrangements  with  solid  bucket  a  small  pipe  is  fitted,  having  a 
branch  to  the  space  between  the  suction  and  the  top  valve.  The 
object  of  this  pipe  is  to  allow  water  from  the  stand  pipe  to  flow 
into  the  pump  and  suction  pipe,  as  at  times,  when  the  pumps 
are  not  working,  the  water  would  flow  past  the  valves,  and  were 
not  the  air  in  the  pipes  ejected  by  the  water  flowing  in  from  the 
stand  pipe,  the  shock  to  the  machinery  would  be  very  great.  There 
are  three  plug  valves,  one  on  each  end  of  the  small  pipe  and 
branch,  to  shut  the  water  off  when  the  pipe  and  pump  are  full, 
which  is  known  by  the  small  pet  plug  tap  placed  below  the  dis- 
charge valve  passing  water — a  sure  sign  that  all  the  air  is  expelled. 
At  the  bottom  of  the  suction  pipe  a  loaded  valve  is  placed  a  little 
above  the  water  in  the  well,  or  sump,  the  technical  term  for  the 
space  below  the  roadway  at  the  pit  bottom  where  the  water  is  col- 
lected. This  valve  is  loaded  to  a  pressure  of  15  lbs.  per  square 
inch,  and  is  used  to  test  the  action  of  the  valves.  Should  the  suction 
valve  be  passing  water  when  the  solid  bucket  is  lifting,  the  valve 
will  discharge  water,  simply  because  the  water  sucked  up  the  air 
pipe  is  forced  down  again,  and  as  it  cannot  pass  the  foot  valve  when 
in  good  working  order,  it  naturally  escapes  at  the  loaded  valve, 
where  the  pressure  on  the  valve  is  not  so  great  as  on  the  discharge 


158 


MODERN   STEAM   PRACTICE. 


valve,  subjected  as  it  is  to  the  full  head  of  water  in  the  stand  or 
delivery  pipe.  This  valve  can  also  be  used  to  test  if  the  discharge 
valve  closes  properly,  the  engine  being  stopped  for  that  purpose; 
the  plug  tap  above  the  suction  valve  and  the  one  on  the  air  pipe  are 
opened,  and  a  communication  through  the  small  pipe  already  men- 
tioned is  effected  between  the  pump  and  the  suction  pipe.  If  the 
discharge  valve  passes  water  the  loaded  valve  at  once  lifts,  being 
acted  on  by  the  full  hydrostatic  head  in  the  delivery  pipe.  This 
valye  is  therefore  of  great  use  in  testing  the  efficient  working  of 

the  pump. 

The  pump  valves  are  gen- 
erally of  the  double  or  treble 
beat  kind.  They  are  intro- 
duced to  obviate  the  objec- 
tions inherent  in  the  flap 
and  conical  type  of  valve, 
due  to  the  great  lift  neces- 
sary in  the  former  to  pass 
the  water,  and  also  on  ac- 
count of  the  full  head  of 
water  in  the  stand  pipe, 
which,  acting  on  a  large 
area,  causes  the  valve  to  shut 
with  great  violence,  tending 
to  shatter  the  machinery 
and  foundations.  This  evil 
is  greatly  obviated  in  the 
double-^eat  valve,  as  it  is 
adapted  to  pass  a  large  body 
of  water  with  a  moderate 
lift,  which  is  the  principal 
object  to  be  attained  in  all 
valves  subjected  to  hydro- 
static pressure.  The  valve 
consists  of  a  metallic  cylin- 
der, contracted  at  the  top, 
having  a  central  ring  with 
arms  radiating  from  it,  and  passing  down  the  side  of  the  cylinder  to 
strengthen  it;  there  is  an  inside  projection  at  the  top  of  the  valve, 
which  is  truly  faced  in  the  turning  lathe,  as  is  also  the  bottom  edge 


Fig.  94. — Double-beat  Valve. 


A,  Valve  seat.      b,  Valve.      c  c,  Wooden  beats. 
D,  Guide  piece.     E,  Flange  and  bolts. 


STATIONARY   ENGINES. 


159 


of  the  cylinder,  the  central  ring  being  accurately  bored  out.  The 
seating  consists  of  a  bottom  ring  and  a  solid  disc  at  the  top,  having 
a  guiding  piece  at  the  top  of  the  disc,  with  a  loose  flange  secured 
by  bolts;  the  bottom  ring  and  disc  plate  are  connected  by  feathers 
or  arms,  cast  all  in  one  piece.  The  bottom  ring  and  top  plate  are 
recessed  for  the  reception  of  a  ring  of  wood  or  soft  metal,  termed 
the  beating  surface.  The  amount  of  contraction  at  the  top  of  the 
valve  is  due  to  its  weight,  and  the  pressure  brought  to  bear  on  it 
should  be  slightly  in  excess  of  the  total  weight  of  the  valve.  Thus 
very  little  force  is  lost  in  lifting  it;  and  as  the  head  of  water  in  the 
discharge  pipe  only  acts  on  a  small  area,  in  comparison  to  the 
water  way  through  the  bottom  ring — and  as  the  lift  of  the  valve  is 
moderate,  owing  to  the  water  being  forced  or  drawn  through  two 
circumferential  openings 
— the  beat  on  the  wooden 
or  white  metal  rings,  if 
so  fitted,  is  very  gentle 
and  but  little  felt,  in 
comparison  with  that 
of  flap  valves  made  of 
leather,  fitted  with  me- 
tallic facings  to  prevent 
the  leather  being  forced 
through  the  seatings. 
For  moderate  lifts,  how- 
ever, and  more  especially 
for  lift  pumps,  the  flap 
valve  is  still  used. 

The  top  and  bottom 
valves,  or  clacks,  as  they 
are  technically  termed, 
have  deep  seatings  of 
cast  iron,  turned  slightly 
conical,  fitting  into  cor- 
responding parts  bored 
out  in  the  pump  cast- 
ings, and  are  fixed  in 
position  with  thin  red 
turned  out  on  the 


Fig.  95.— Clack  Valve  with  Leather  Hinge. 

A,  Clack  seat,     b,  Leather  disc,     c  c,  Top  and  bottom  plates. 

D,  Bow.     E,  Cross  piece  with  cotter  for  securing  the  bars. 

F  F,  Recesses. 


lead   and    spun   yarn    laid    into   recesses 
circumference  of  the   seat;   there  is  a  single 
feather  cast  along  with  the  seat,  having  an  oblong  hole  in  the  centre. 


i6o 


MODERN   STEAM  PRACTICE. 


n 


The  valve  is  a  disc  of  leather,  with  top  and  bottom  plates  of  wrought 
iron,  securely  rivetted  through  and  through,  and  it  is  held  in 
position  by  a  central  bar  of  iron,  with  long   projections  on  the 

under  side  for  taking  the  entire 
diameter  of  the  valve.  A  key  is 
driven  through  the  bar,  drawing  it 
up  against  the  under  side  of  the 
seating,  which  likewise  presses 
down  the  bar  placed  on  the  top  of 
the  leather;  thus  the  valve  hinges, 
as  it  were,  on  the  mid  feather,  and 
is  perfectly  water-tight.  The  valve 
is  prevented  from  opening  too  far 
by  pieces  forged  on  the  bar,  and  at 
the  top  of  the  bar  a  bow  is  formed, 
for  attaching  a  hook  and  chain 
when  drawing  the  clack  from 
the  surface,  as  provision  must  be 
made  that  the  clack  can  be  drawn 
when  the  water  is  above  the  valve- 
chest  door.  Some  of  these  valves 
hinge  on  a  bar,  which  passes 
through  lugs  forged  on  the  top 
plate  and  through  holes  in  the 
bow,  for  fishing  the  valve  to  which 
the  bow  is  securely  bolted;  there 
is  also  a  wrought-iron  piece  at  the 
centre  of  the  valve  seating  on  which 
the  valve  hinges.  There  should  be 
a  slight  play  in  the  holes  to  suit 
the  varying  thickness  of  the  leather 
forming  the  valve. 
The  -working  bucket  (Fig.  97)  is  constructed  similarly  to  the 
ordinary  clack  valve  with  leather  hinge,  having  means  of  attaching 
the  bar  to  the  pump  rods;  and  is  packed  with  deep  rings  of  gutta- 
percha, let  into  recesses  formed  on  the  outside  circumference,  and 
pressed  against  the  barrel  with  hydraulic  pressure,  holes  being  bored 
from  the  top  of  the  bucket  for  this  purpose.  This  plan  is  much 
more  preferable  than  the  old  mode  of  packing  the  bucket  with  a 
plaited  gasket  or  ring  of  leather. 


1 — I c. I — » . 


Jl OL. 


Fig.  96. — Clack  Valve  with  Wrought-iron 
Hinge  Plates. 

A,  Clack  seat,  b.  Leather  disc,  cc,  Hinge 
plates.  D,  Round  bar  for  hinge,  e.  Bow. 
F,  Centre  stud. 


STATIONARY  ENGINES. 


l6l 


The  economy  of  the  single-acting  pumping  engine  depends  on  the 
high  steam  pressure  adopted — the  higher  the  pressure  in  the  boiler 
is  the  less  water  is  required  to  be  evaporated  or  boiled  off  propor- 


A,  Bucket.  B,  Leather  disc.  C  C,  Top  and  bottom  plates,  d  d,  Gutta-percha  rings.  E,  Holes  for 
water  pressure  for  the  packing  rings,  f.  Rod.  g.  Cross  bar  for  securing  the  rod  with  jib  and 
cotter. 

tionally;  and,  in  addition,  the  facility  of  cutting  off  the  steam  at  any 
part  of  the  stroke  to  suit  the  load  on  the  engine,  and  the  careful  cloth- 
ing of  all  the  parts  where  radiation  takes  place  with  a  non-conducting 
material,  keeping  those  parts  warm  and  the  surrounding  atmosphere 
cool.  To  effect  this  the  cylinder  is  surrounded  with  a  steam  casing 
or  outer  cylinder.  Steam  is  admitted  between  these  two,  and  the 
outer  one  is  covered  with  felt  and  wood  over  all,  and  in  some  cases 
brickwork ;  the  cylinder  cover  is  hollow,  admitting  steam,  and  it  is 

protected  with  wood  laggings   as  it   is   technically  termed.     The 

11 


1 62 


MODERN    STEAM    PRACTICE. 


Steam  pipes  are  covered  with  felt  and  canvas,  and  the  valve  chests 
with  felt  and  wood,  neatly  covered  in  with  ornamental  plates.  The 
boilers  are  protected  with  fire-brick  or  other  material  on  the  top. 
Thus,  with  all  these  precautions,  very  little  radiation  takes  place, 
even  although  the  engine  may  not  have  been  working  for  a  consid- 
erable time. 

The  action  of  the  single-acting  pumping  engine  is  quite  different 
from  that  of  the  reciprocating  engine,  having  the  connecting  rod 
coupled  to  a  crank  shaft.  The  steam  from  the  boiler  only  acts  on 
the  top  of  the  piston,  lifting  the  water  at  the  other  end  of  the  beam, 
or  as  it  were  the  IN-stroke  of  the  pump,  when  lifting  pumps  are  fitted; 


Fig.  g8. — Equilibrium  Valve. 
A,  Valve.     B,  Spindle  for  valve,     c,  Seat  for  valve,     d,  Holding-down  bolt,     e,  Cross  bar. 

and  when  forcing  sets  are  used  in  connection  with  lifting  pumps,  as 
is  often  the  case  when  pits  are  very  deep,  the  water  is  forced  up  the 
stand  pipe  by  the  mere  weight  of  the  pump  rods,  &c. 

The  valves  are  of  the  equilibrium  kind;  two  are  fitted  to  the  top 


STATIONARY  ENGINES. 


163 


chest,  namely,  the  steam  and  equilibrium  valves,  and  the  exhaust 
valve  is  placed  in  the  bottom  chest  There  is  likewise,  in  some 
examples,  a  regulating  valve  worked  by  hand,  for  regulating  the 
supply  of  steam  from  the  boiler;  and  a  throttle  valve  is  placed  in 


W/////////////^/ 


Fig.  99. — Nozzle-valve  Chest  boxed  in. 

A,  Steam-valve  seating.  B,  Equilibrium-valve  seating. 
C  C,  Exhaust-valve  seating.  D,  Regulating-valve 
seating,  e,  Pipe  for  conveying  the  steam  from  the 
top  to  the  bottom  of  the  cylinder. 


Fig.  100. — Nozzle-valve  Chest  not  boxed  in. 

A,  Steam-valve  seating.  B,  Equilibrium-valve 
seating,  c.  Exhaust-valve  seating.  E  E,  Pipes 
for  conveying  the  steam  from  the  top  to  the 
bottom  of  the  cylinder. 


the  pipe  communicaimg  with  the  top  and  bottom  valve  chests,  which 
is  also  regulated  by  hand,  and  is  introduced  to  throttle,  or  rather 
wire-draw  the  steam  after  passing  through  the  equilibrium  valve; 
thus  the  engineman  can  control  the  upstroke  of  the  piston  with  the 
greatest  nicety  without  requiring  to  alter  the  lift  of  the  equilibrium 
valve. 

There  are  three  shafts  or  arbors  placed  across  the  engine,  arranged 
one  above  another  in  a  vertical  line;  the  top  one  is  for  the  steam- 


164 


MODERN   STEAM   PRACTICE. 


valve  gear,  the  middle  one  for  the  equilibrium,  and  the  bottom  shaft 
for  the  exhaust-valve  gear.  An  arm  is  keyed  on  each  shaft,  having 
a  connecting  rod  coupled  to  the  lever  for  lifting  each  valve;  each 
shaft  has  also  an  arm  with  a  connecting  rod  passing  downwards  to 
a  loaded  lever,  the  weight  of  which  lifts  each  valve  respectively. 

O — — O Q 


Steam,  cut  off 


&-■-: 


Fig.  loi. — Cornish  Valve  Gear. 


The  valves  are  shut  with  tappets  placed  on  the  vertical  rod  worked 
by  the  engine,  and  named  the  plug  rod;  the  tappets  act  on  slide 


STATIONARY  ENGINES.  165 

handles  or  horns  keyed  to  each  shaft  The  tappet  or  sHding  bar  for 
the  steam  valve  is  a  long  wrought-iron  bar,  quite  parallel  in  its 
entire  length,  secured  to  the  plug  rod  with  eyes  at  the  ends,  and 
set  screws  passing  through  these  eyes,  the  point  of  the  screw  press- 
ing against  the  plug  rod.  This  is  necessary,  as  the  steam  may  be  cut 
off  quickly,  or  say  at  one-fourth  of  the  stroke  of  the  piston,  conse- 
quently the  bar  would  require  to  be  somewhat  more  than  three- 
fourths  of  the  stroke  of  the  plug  rod,  so  as  to  keep  the  steam  valve 
shut.  The  two  other  tappets  are  round  arms,  secured  to  the  plug 
rod  in  the  same  way,  having  a  series  of  leather  washers  screwed  up 
against  a  collar,  with  a  nut  and  metal  washer  at  the  end  of  the 
projecting  bar.  On  the  steam  and  exhaust  shafts  a  catch  and  paul 
are  fitted  for  each,  keeping  the  valves  shut  until  released  by  the 
cataract,  which  consists  of  a  pump  worked  by  the  down  stroke  of 
the  plug  rod,  with  a  weighted  lever  so  arranged  that  the  oil  or  water 
is  forced  out  of  the  pump,  the  delivery  being  regulated  by  a  valve 
or  plug  tap.  On  the  end  of  the  weighted  lever  there  is  a  rod 
passing  upwards  for  raising  the  pauls,  which  can  be  adjusted  at 
pleasure;  thus  the  catches  are  freed,  and  the  weight  arm  lifts  the 
valve.  A  quadrant  is  keyed  on  the  middle  and  bottom  shaft  to 
keep  the  equilibrium  valve  shut.  When  the  exhaust  valve  is  open 
the  top  quadrant  abuts  on  the  lower  one,  and  keeps  the  equilibrium 
valve  shut  until  it  is  released,  when  the  tappet  for  the  bottom  shuts 
off  the  exhaust,  and  allows  the  quadrant  to  pass  the  equilibrium 
quadrant,  thus  releasing  it,  and  the  valve  is  instantly  opened  by 
the  weight  arm. 

Now  we  will  suppose  the  piston  at  the  top  of  the  cylinder,  and 
the  exhaust  valve  full  open  by  the  cataract  releasing  the  bottom 
catch;  the  cataract  rod,  still  moving  upwards,  releases  the  top  catch, 
and  the  steam  valve  is  instantly  raised  by  the  weight-arm,  the  piston 
at  once  descends,  until  the  long  parallel  tappet  cuts  off  the  steam;  the 
plug  rod  still  moves  on  until  one  of  the  tappets  shuts  the  exhaust  at 
the  end  of  the  piston  stroke,  and  as  the  equilibrium  valve  was  held 
in  position  by  its  quadrant,  at  the  moment  the  exhaust  is  shut  the 
equilibrium  valve  opens;  so  the  steam  is  thus  allowed  to  escape 
from  the  top  of  the  piston  to  the  under  side  of  it,  the  descent  of  the 
pump  rods  placed  at  the  other  end  of  the  engine  beam  being  regu- 
lated by  the  amount  of  opening  of  the  equilibrium  valve,  which  can 
be  further  regulated  by  the  throttle  valve  at  pleasure  wire-drawing 
the  steam  in  the  passages  from  the  top  to  the  under  side  of  the 


l66  MODERN   STEAM   PRACTICE. 

piston;  and  in  this  way  the  outgoing  stroke  or  descent  of  the  pump 
rods  may  be  very  slow  indeed.  The  plug  rod,  ascending,  shuts  off 
the  equilibrium  valve,  thus  stopping  the  further  descent,  or  produc- 
ing only  a  slight  motion,  of  the  plunger  and  weight,  until  the 
cataract  releases  the  exhaust  and  then  the  steam  valve.  It  will 
thus  be  seen  that  for  a  part  of  the  downward  stroke  the  steam  and 
exhaust  valves  are  both  open,  and  the  exhaust  remains  so  until  the 
end  of  the  stroke,  when  it  is  closed;  while  in  the  up  stroke  of  the 
piston  the  equilibrium  valve  is  open,  and  all  the  rest  shut  off. 

In  order  still  further  to  explain  this  intricate  valve  gear,  in  Figs. 
102,  103,  we  give  an  example  fitted  to  an  engine  at  one  of  our 
Cornwall  mines,  the  diameter  of  the  steam  cylinder  being  90  inches. 
"  The  action  of  the  gear  will  be  better  understood  if  we  describe 
each  stroke  separately.  First,  the  steam,  or  indoor  stroke: — This  is 
the  down  stroke  of  the  piston,  and  is  produced  by  the  admission  of 
steam  through  a  valve  termed  the  steam  valve,  situated  in  the  top 
nozzle,  and  which  is  actuated  by  means  of  the  lever  B  fixed  on  an 
arbor  carried  in  bearings  in  the  two  upright  castings  at  the  sides, 
which  are  termed  arbor  posts.  It  is  usual  to  connect  the  lever  B 
directly  with  the  steam-valve  lever — by  means  of  a  rod  carried  up- 
ward, instead  of  indirectly  by  means  of  a  rod  carried  downwards,  as 
in  the  example  before  us;  the  reason  for  the  latter  arrangement  we 
will  explain  as  we  go  on.  The  lever  B  is  attached  by  means  of  a 
rod  with  a  'treadle'  or  weighted  lever  of  wood  situated  under  the 
engine-house  floor;  the  treadle  is  connected  to  the  steam-valve 
lever,  so  that  when  the  lever  B  is  raised  it  closes  the  steam  valve. 
On  the  steam  arbor,  or  the  arbor  carrying  the  lever  B,  is  placed 
a  quadrant  K,  which  is  supported  by  means  of  the  catch  U,  which 
catch  keeps  the  steam  valve  closed  till  the  cataract  rod  A  shall 
have  released  the  quadrant  K  by  means  of  the  lever  M,  and  thus 
allowed  the  weighted  treadle  to  pull  down  the  lever  B  and  open  the 
steam  valve.  The  cataract  is  actually  the  governor  of  the  engine, 
and  acts  in  the  following  way.  (See  illustrations  of  cataracts.  Figs. 
104,  105,  106.)  In  this  case  a  plunger  is  attached  to  the  lever,  on 
the  opposite  side  of  the  fulcrum  is  placed  the  cataract  rod  A,  and 
on  the  plunger  side  of  the  fulcrum  a  weight.  The  plunger  works 
in  a  kind  of  force  pump,  fixed  in  a  cistern  full  of  water.  When  the 
plunger  is  raised  water  follows  it  up  through  the  suction  valve,  and 
during  the  down  stroke  the  water  thus  drawn  from  the  cistern  is 
forced  back  again  through  a  delivery  valve  which  is  capable  of  being 


STATIONARY   ENGINES.  16/ 

varied  in  the  height  of  its  lift  by  means  of  a  screw  on  the  cataract 
governor  valve  rod,  which  rod  is  under  command  of  the  engine- 
driver.  It  is  evident  that  the  smaller  the  opening  of  the  delivery 
valve  the  slower  will  the  plunger  descend,  the  weight  forcing  it 
being  constant.  As  the  plunger  descends  the  rod  A  rises,  and  brings 
the  roller  shown  in  the  front  elevation  to  bear  on  the  lever  M,  and 
thus  releases  the.  quadrant  K.  Let  the  cataract  plunger  be  up,  then 
the  engine  is  at  rest,  and  remains  so  until  the  rod  A  shall  have  raised 
the  lever  M  and  released  the  catch  U;  the  weight  attached  to  B  then 
suddenly  falls  and  opens  the  steam  valve.  Steam  being  suddenly  let 
in  on  the  piston  causes  it  to  commence  its  indoor  stroke,  and  in  doing 
so  to  give  a  downward  direction  to  the  motion  of  the  plug  rod  S,  the 
tappets  of  which  coming  into  contact  with  the  steam  horns  depress 
them,  and  thus  raising  the  lever  B  close  the  steam  valve,  at  the  same 
time  the  piston  continues  its  stroke  under  the  expansive  force  of  the 
steam  in  the  cylinder,  and  towards  the  end  of  the  stroke  raises  the 
plunger  of  the  cataract  to  prepare  it  to  repeat  its  functions  during 
the  next  indoor  stroke.  The  horn  or  lever  of  the  cataract  being  thus 
depressed  whilst  the  steam  valve  is  closed,  the  catch  U  falls  under  the 
influence  of  the  weight  of  the  lever  M  under  the  projection  on  the  cir- 
cumference of  the  quadrant  K,  thus  preventing  the  opening  of  the 
steam  valve  when  the  steam  tappets  have  been  raised,  during  the  up 
or  outdoor  stroke  of  the  piston,  above  or  clear  of  the  steam  horns,  until 
the  cataract  weight  shall  have  fallen  sufficiently  far  to  release  the  catch 
U,  when  the  steam  valve  suddenly  opens,  as  before  described,  and 
the  next  indoor  stroke  is  commenced.  Having  described  the  func- 
tions of  the  steam  or  top  arbor  and  tappets,  we  will  consider  next 
the  equilibrium  stroke.  The  middle  is  the  equilibrium  arbor,  and 
the  horn  is  shown  in  the  side  elevation.  There  are  two  quadrants  on 
this  arbor.  The  first  G  is  released  by  means  of  a  cataract  constructed 
precisely  like  the  one  just  described.  The  rod  of  this  cataract  is 
placed  inside  the  gear  posts,  as  shown  on  the  front  elevation,  whereas 
that  of  the  steam  cataract  is  placed  on  the  outside.  There  is  an 
adjusting  screw  A  on  the  equilibrium  cataract  rod,  and  two  such,  P, 
on  that  of  the  steam  cataract.  The  lever  C  opens  and  closes  the 
equilibrium  valve.  The  opening  is  done  by  means  of  a  counter-weight 
attached  to  the  lever  E,  which  operates  on  the  release  of  the  quadrant 
G.  At  the  completion  of  the  indoor  stroke  the  piston  pauses  until 
the  catch  O,  actuated  by  means  of  the  cataract,  releases  the  quadrant 
G.    It  will  be  seen  that  this  cataract  rod  releases  on  its  down  stroke, 


i63 


MODERN  STEAM   PRACTICE. 


Fig.  I02. — Valve  Gear  of  a  90-inch  Cornish  Pumping  Engine. — Front  Elevation. 


whereas  the  other  does  it  on  its  up  stroke.    In  the  former  case  the  rod 


STATIONARY  ENGINES. 


169 


Fi^.  103. — Valve  Gear  of  a  go-inch  Cornish  Pumping  Engine. — Side  Elevation. 

A  is  attached  to  the  cataract  lever  on  the  same  side  of  the  fulcrum  as 


I/O  MODERN   STEAM   PRACTICE, 

the  plunger.  The  quadrant  G  being  released,  the  equilibrium  valve  at 
the  top  of  the  cylinder  suddenly  opens,  and  a  free  communication 
is  established  between  the  top  and  bottom  sides  of  the  piston  through 
the  perpendicular  or  equilibrium  pipes  shown  in  outline  on  the 
woodcut.  The  outdoor  stroke  now  commences;  the  piston,  being  in 
equilibrium,  is  raised  by  means  of  the  weight  of  the  pump  rods  and 
attachments,  which  is  sufficient  to  force  the  water  in  the  pumps  and 
overcome  all  other  resistances.  During  this  stroke  the  plug  rods 
move  upward,  and  towards  the  end  the  equilibrium  tappet  comes 
in  contact  with  the  horn  on  the  equilibrium  arbor,  and  lifting  it 
closes  the  valve,  at  the  same  time  allowing  the  catch  O  to  fall  under 
the  projection  on  the  quadrant  G.  A  portion  of  steam  is  thus 
confined  in  the  top  of  the  cylinder,  which  gradually  brings  the  piston 
to  rest,  and  prevents  it  striking  the  cover.  The  piston  now  pauses 
till  the  steam  quadrant  shall  be  released.  The  eduction  stroke  is 
performed  simultaneously  with  the  steam  stroke.  The  eduction 
valve  is  situated  in  the  bottom  nozzle,  and  opens  a  passage  to  the 
condenser  for  the  steam  passed  from  the  top  to  the  under  side  of  the 
piston  during  the  equilibrium  stroke.  The  lever  D  actuates  the 
valve  through  the  lever  T.  As  the  piston  completes  its  indoor 
stroke  the  eduction  tappet  comes  into  contact  with  a  horn  on  the 
eduction  or  lower  arbor.  The  valve  is  opened  by  means  of  a  coun- 
terweight at  F,  when  the  quadrant  L  is  released  by  the  cataract. 
The  quadrants  H  and  I  are  for  the  purpose  of  keeping  the  equilibrium 
valve  closed  until  the  closing  of  the  eduction  valve.  It  will  be  seen 
that,  although  the  catch  O  may  be  released,  the  quadrant  H  prevents 
the  opening  of  the  equilibrium  valve  until  the  eduction  valve  is 
closed  and  the  quadrant  H  brought  into  the  position  shown  on  the 
woodcut.  It  will  be  seen  that  if  the  catches  M  and  N  are  released 
simultaneously  the  steam  and  eduction  valves  will  open  at  the  same 
time,  but  the  times  can  be  varied  by  means  of  the  adjusting  screws 
P  and  R.  The  hand  wheel  X  is  for  the  purpose  of  adjusting  the 
ameunt  of  fall  given  to  the  weight  which  opens  the  steam  valve,  so 
as  to  give  the  valve  a  greater  or  less  opening.  The  degree  of 
expansion  is  varied  on  the  plug  rod  by  means  of  the  screw  S."^ 

The  cataract,  as  a  means  of  regulating  the  number  of  strokes  of 
the  Cornish  pumping  engine,  is  exceedingly  simple.  One  arrange- 
ment consists  of  a  wooden  box,  open  at  the  top,  fitted  with  another 
box  internally,  having  flap  valves  at  the  bottom  opening  upwards^ 

*  The  Engineer. 


STATIONARY   ENGINES. 


171 


as  also  a  plug  tap,  which  can  be  regulated  at  pleasure  from  the 
engine-room  floor.  There  is  a  central  rod  secured  through  the 
bottom  of  this  internal  box  or 
tray,  and  connected  to  a  lever 
weighted  at  the  end,  with  a  fixed 
pin  as  the  fulcrum,  placed  be- 
tween the  weight  and  the  box ; 
this  weight  is  slightly  in  excess 
of  the  tray  and  adjuncts  when 
the  internal  box  is  full  of  water. 
The  action  is  as  follows: — The 
outside  box,  in  the  first  place, 
must  be  nearly  full  of  water,  and 
we  will  suppose  the  tray  empty 
and  raised  by  the  weight  acting 
through  the  oscillating  lever;  the 
plug  rod  of  the  engine  descend- 
ing acts  on  mechanism  that  de- 
presses the  tray,  and  water  flows 
through  the  flap  valves  in  the  bot- 
tom until  the  plug  rod  ascends, 
when  the  preponderance  of  the  weighted  lever  raises  the  internal 
box  or  tray  above  the  level  of  the  water  in  the  outside  box,  conse- 
quently the  water  in  the  tray  gravitates  into  the  external  reservoir — 
hence  the  name  cataract;  and  the  time  the  water  takes  to  flow  out 
of  the  one  into  the  other  is  regulated  by  the  plug  tap, — if  it  is  full 
open  the  water  will  flow  out  quickly,  and  the  tray  will  rapidly 
ascend,  the  cataract  rod  releasing  the  valves;  but  should  the  plug 
tap  be  nearly  closed,  it  is  evident  that  the  water  will  flow  out  of  the 
tray  slowly;  and  as  this  tap  is  regulated,  the  number  of  strokes  of 
the  engine  will  be  increased  or  diminished:  but  the  number  of  strokes 
rarely  exceeds  twelve  per  minute  as  the  maximum,  and  four  per 
minute  as  the  minimum.  This  form  of  cataract  is  exceedingly 
simple,  and  even  rude  in  construction,  yet  it  answers  the  purpose 
admirably  so  long  as  the  level  of  water  is  maintained  in  the  external 
box,  which  must  be  looked  to  occasionally,  as  evaporation  will  take 
place  or  leakage  occur. 

Instead  of  the  wooden  tray  a  plunger  pump  (Fig.  105)  is  sometimes 
fitted  inside  of  a  box  of  cast  iron,  having  a  valve  at  the  bottom  for 
admitting  water  or  oil  into  the  pump,  fitted  with  a  tap  for  regulating 


Fig.  104. — Cataract  with  Wooden  Tray. 

A,  Box  for  water.       B,  Tray.       c,  Inlet  valve. 
D,  Regulating  valve,     e,  Small  hand  wheel. 


1/2 


MODERN   STEAM   PRACTICE. 


the  exit  of  the  fluid.   The  weighted  lever  is  so  arranged  that  the  plug 
rod  lifts  the  plunger  and  weight,  and  the  cataract  rod  for  disengag- 


Si 


Fig.  105. — Cataract  with  Plunger  Pump. 

A,  Cast-iron  box.      B,  Plunger,    c.  Inlet  valve,      d,  Plug  rod.      E,  Lever,      r,  Weight 

G,  Regulating  spindle  and  valve. 

ing  the  valves  ascends  as  the  plunger  and  weight  descend,  the 
motion  being  changed  by  a  lever;  the  cataract  rod  for  lifting  the 
paul  is  jointed  at  one  end  of  the  lever,  and  the  rod  passing  down  to 
the  arm  for  the  weight  and  plunger  at  the  other  end. 

In  some  examples  of  the  plunger  type,  when  two  cataracts  are  used, 
the  plug-rod  tappet  acts  on  the  two  levers  for  lifting  the  plungers 
simultaneously;  on  the  centre  of  motion  of  the  levers  a  grooved 
wheel  is  fixed,  and  the  lever  for  the  cataract  pump  is  connected  by 
means  of  a  chain  wound  round  the  wheels,  and  as  the  tappet  or 
plug  rod  comes  in  contact  with  the  levers  the  wheels  are  partially 
turned  round,  pulling  one  end  of  the  cataract  lever  down,  and 
raising  the  other  end,  to  which  the  plunger  and  weight  are  fitted. 
Some  arrangements  of  cataract  pumps  have  a  solid  piston,  or  one 
fitted  with  cupped  leather  washers,  and  on  the  top  of  the  piston  rod 
a  crosshead  and  side  rods  passing  down  under  the  floor  of  the 
engine  house,  and  in  communication  with  the  mechanism  for  lifting 
the  piston  and  weight  placed  on  the  top  of  the  crosshead.  A  central 
metallic  valve  is  placed  at  the  bottom  of  the  pump,  and  a  tap  is 
likewise  fitted  for  regulating  the  ejection  of  the  oil,  which  is  gene- 
rally used  when  the  cataract  is  placed  on  the  engine-room  floor. 
This  type  of  cataract  has  likewise  a  reservoir  for  receiving  and  sup- 
plying the  oil;  and  as  leakage  past  the  piston  ring  occurs  after 
being  long  in  use,  an  air  passage  is  formed  above  the  piston  in 
communication  with  the  reservoir,  and  any  oil  passing  the  piston  is 


STATIONARY  ENGINES. 


173 


allowed  to  fall  by  gravitation  into  the  cistern  or  metallic  box.  In 
another  example,  where  refinement  of  construction  is  a  desideratum, 
the  cistern  is  dispensed  with,  and  the  oil  is 
ejected  through  a  valve  fitted  to  the  piston 
on  the  down  stroke,  and  passes  through  the 
same  valve  on  the  up  stroke,  it  being  forced 
through  by  suitable  mechanism  in  the 
down  stroke,  and  the  ascent  of  the  piston 
is  acted  on  by  the  weight,  as  in  the  former 
examples.  This  plan  of  cataract  necessi- 
tates a  hollow  piston  rod,  with  stuffing  box 
on  the  pump  cover,  fitted  with  an  internal 
rod  attached  to  the  valve,  passing  up  to  the 
crosshead,  for  taking  the  disengaging  rod; 
this  hollow  rod  is  fitted  with  a  stuffing  box, 
and  the  internal  rod  has  a  thumb  screw  at 
the  top  for  regulating  the  lift  of  the  valve. 
Thus  this  valve  allows  of  the  oil  passing 
from  the  bottom  to  the  top  of  the  piston, 
and  also  regulates  the  flow  of  the  oil  from 
the  top  of  the  piston  to  the  under  side  of 
it,  forming  a  self-contained  and  handsome 
cataract  pump. 

The  condenser  (Fig.  107)  for  the  Cornish 
engine  is  generally  a  separate  vessel,  worked 
on  the  injection  principle.  As  the  exhaust 
pipe  from  the  steam  cylinder  is  of  large 
diameter  and  of  considerable  length,  it  is  obvious  that  the  cubical 
contents  of  the  condenser  need  not  be  so  large  as  for  ordinary 
engines,  the  exhaust  pipe  acting  as  a  receiver,  and  the  steam  being 
condensed  in  a  vessel  placed  at  the  extreme  end. 

The  air  pump  is  of  the  ordinary  kind,  with  metallic  head  and  foot 
valves,  the  bucket  being  open,  with  a  metallic  valve  placed  on  the 
top,  and  it  is  made  tight  with  ordinary  hemp  packing  plaited,  or  what 
is  termed  a  gasket.  In  another  example  (Fig.  108)  the  air  pump  and 
condensing  vessel  are  placed  inside  of  a  cast-iron  tank,  which  is  kept 
constantly  full  by  means  of  a  pump  termed  the  cold-water  pump. 
When  this  arrangement  is  adopted  the  condensing  vessel  is  kept  quite 
cool  by  the  surrounding  water,  and  to  a  certain  extent  acts  as  a  surface 
condenser,  in  combination  with  the  injection  system.     The  tank 


Fig.  106. — Cataract  without  Cistern. 

A,  Cylinder,     b,  Cupped  leather  pis- 
ton with  valve.       c.  Hollow  rod. 

D,  Stuffing     box      and      gland. 

E,  Thumb  screw  and  gland. 


174 


MODERN   STEAM   PRACTICE. 


Fig.  107. — Condenser  and  Air  Pump,  with  Foot- valve  Seating. 
A,  Condenser.     B,  Air  pump,     c,  Foot-valve  chest. 


o) 


^ 


^^^ 


3^^^^^..^^kk^^^^^l.^k^^^^^^>k^k'.^-.^^'.■.k■.k^^^^■.'.^^^■.■.ss^^S^^^S^',S'^;V^^?^^<^ 


Fig.  108. — Air  Pump  and  Condenser  without  Foot  Valve  contained  in  a  cast-iron  Tank. 
A,  Condenser,     b,  Air  pump,     c.  Tank. 


STATIONARY   ENGINES. 


175 


must  be  fitted  with  an  overflow  pipe,  which  is  placed  in  communi- 
cation with  the  discharge  from  the  air  pump.  When  the  water  is 
very  bad  the  air  pump  should  be  lined  with  a  barrel  of  composition 
metal,  or  a  brass  barrel  is  so  placed,  centrally  with  the  condenser; 
and  when  suitably  strengthened  and  supported  from  the  con- 
denser vessel,  the  latter  proves  a  very  compact  arrangement,  com- 
bining the  condenser  and  air  pump  in  one.  The  foot  valve,  in 
ordinary  arrangements,  is  placed  at  the  bottom,  between  the  con- 
denser and  air  pump.  It  is  a  flap  valve  hinged  vertically,  and  is 
sometimes  made  of  wrought  iron,  faced  with  a  brass  beating  surface, 
with  a  corresponding  brass  face  securely  pinned  on  the  cast-iron 
seat.  The  valve  is  bent  to  form  a  hooked  hinge,  so  that  it  can  be 
readily  taken  off"  the  spindle  on  which  it  hinges  without  disturbing 
the  seat,  a  door  being  fitted  to  the  condenser  casting  for  inspecting 


Fig.  109. — Head  Valve  with  Wooden  Beat 
on  Seat. 

A,  Valve.     B,  Seat,     c  c,  Wooden  beat. 
D,  Stuffing  box  and  gland. 


Fig.  no. — ^Air-pump  Bucket,  with  Brass  Seat  for 
India-rubber  Valve. 

A,  Bucket.     B,  Brass  seat  for  valve,      c,  India- 
rubber  disc.     D,  Guard.     E,  Rod  secured  with 
a  nut  at  the  bottom. 


and  adjusting  the  valve.  The  head  valve,  placed  at  the  top  of  the 
air  pump,  is  a  disc  of  metal  having  a  deep  boss  at  its  centre, 
strengthened  with  ribs  radiating  from  the  centre,  and  having  a  hole 
bored  through  the  boss  for  receiving  the  air-pump  rod,  which  acts 
as  a  guide  for  the  valve.    Sometimes  this  boss  is  fitted  with  a  gland 


176  MODERN    STEAM   PRACTICE. 

and  packing  space,  thus  making  it  perfectly  water-tight.  The  seat 
in  this  example  is  cast  separate,  and  bolted  to  the  air-pump,  and 
fitted  with  a  ring  of  wood  for  the  valve  to  beat  against.  The  valve 
fitted  to  the  top  of  the  air-pump  bucket  is  of  a  similar  description, 
with  a  plain  hole  lined  with  brass,  which  acts  as  a  guide.  In  some 
cases  the  valve  on  the  bucket  (Fig.  no)  is  of  india  rubber,  working 
on  a  grating  of  brass  bolted  to  the  bucket.  The  air-pump  bucket 
is  fitted  with  a  junk  ring  and  packing  space,  and  when  a  brass 
barrel  is  used  may  be  packed  with  hemp,  or  a  metallic,  or  even 
wood  packing  will  be  found  to  answer.  Thin  metallic  rings  sprung 
into  recesses  make  a  first-class  packing,  and  last  much  longer  than 
hemp. 

The  Ejector  Condenser. — In  the  ejector  condenser  the  air  pump  is 
entirely  dispensed  with.  The  principle  of  the  apparatus  may  be 
described  as  follows : — In  every  injection  condenser  the  cold  water 
rushes  into  the  vacuum  with  a  velocity  of  about  43  to  44  feet  per 
second;  while  the  exhaust  steam  from  the  cylinder  of  the  engine,  at 
the  pressure  of  10  lbs.  per  square  inch  below  the  atmosphere,  rushes 
into  the  condenser  with  a  velocity  of  about  1 200  feet  per  second,  when 
a  vacuum  of  25  inches  of  mercury  is  maintained.  In  the  common 
condenser  these  rapid  motions  of  the  water  and  the  steam  are  com- 
pletely checked,  and  their  energy  is  wasted,  and  hence  an  air  pump  is 
imperative,  so  as  to  extract  the  water,  air,  and  condensed  steam  from 
the  condenser.  In  the  ejector  condenser  the  exhaust  steam  from  the 
cylinder  of  the  engine  after  each  stroke  is  so  directed  through  a 
discharge  nozzle  as  to  unite  in  a  jet  with  the  condensing  water,  by 
which  it  is  itself  condensed,  having,  however,  imparted  a  sufficient 
velocity  to  the  combined  jet  to  enable  it  to  issue  directly  into  the 
atmosphere  in  a  continuous  yet  impulsive  stream.  The  contents 
of  the  condenser,  both  water  and  air,  are  thus  ejected  without  the 
use  of  an  air  pump,  and  at  the  same  time  without  impairing  the 
vacuum  in  the  condenser.  This  result  is  obtained,  however  low  the 
pressure  may  be  to  which  the  steam  is  expanded  before  the  exhaust 
from  the  cylinder  takes  place,  if  the  injection  water  be  supplied 
with  a  few  feet  of  head  pressure:  and  the  effect  is  produced  by 
taking  advantage  of  the  high  velocity  at  which  the  exhaust  steam 
and  the  injection  water  flow  into  a  vacuum.  The  ejector  condenser 
not  only  discharges  the  products  of  condensation  into  the  atmo- 
sphere from  a  pressure  of  12  lbs.  per  square  inch  below  the  atmo- 
sphere, but  with  a  steam  pressure  equal  to  the  atmosphere  at  the 


STATIONARY   ENGINES. 


177 


commencement  of  the  exhaust,  the  condenser,  when  apphed  to  a 
pair  of  coupled  engines,  is  found  capable  of  lifting  the  condensing 
water  from  a  lower  level  of  6  to  8  feet,  or  raising  the  discharged 
water  to  a  proportionate  height  above  the  condenser. 

In  the  simplest  arrangement  the  injection  water  enters  the  con- 
denser in  the  form  of  a  central  jet  through  the  conoidal  nozzle 
A,  which  is  supplied  by  the  branch 
pipe  B;  and  the  area  of  the  ori- 
fice is  regulated  by  an  adjustable 
central  spindle  C,  which  is  raised 
and  lowered  by  an  external  screw 
and  hand  wheel.  The  exhaust 
steam  entering  at  the  branch  pipe 
D,  passes  through  the  annular 
space  surrounding  the  central 
water  jet,  and  the  combined  cur- 
rent passes  on  through  the  fixed 
conoidal  nozzle  F,  into  the  dis- 
charge tube  G  leading  to  the 
hot  well.  This  tube  is  trumpet- 
mouthed,  so  as  gradually  to  di- 
minish the  velocity  of  the  current 
as  it  passes  through,  and  utilize 
its  moving  force  by  avoiding  use- 
less velocity  at  the  point  of  dis- 
charge, the  enlargement  of  the 
tube  increasing  more  rapidly  to- 
wards its  outer  extremity. 

In  starting  the  condenser  the 
centre  spindle  is  raised  by  means 
of  the  hand  wheel,  and  a  jet  of  injection  water  is  discharged 
through  the  centre  of  the  current  of  the  exhaust  steam  from  the 
engine:  the  injection  water  being  in  this  case  supplied  from  a  head 
of  water  a  few  feet  above  the  condenser,  so  as  to  flow  into  it  by 
gravity.  The  condensation  of  the  steam  by  contact  with  the  injec- 
tion jet  produces  a  vacuum  within  the  condenser,  and  the  water 
then  enters  with  the  velocity  due  to  the  difference  of  pressure  between 
the  external  atmosphere  and  the  degree  of  vacuum  maintained  in 
the  condenser,  added  to  the  velocity  due  to  the  head  of  water  in 

the  injection  supply.     The  water  jet  having  a  straight  passage  for 

12 


Fig.  III. — Condenser  supplied  with  Head 
of  Injection  Water. 


l/S  MODERN    STEAM   PRACTICE. 

its  exit,  without  any  obstruction,  retains  its  initial  velocity,  and 
rushes  on  through  the  combining  nozzle  F  and  the  expanding  dis- 
charge tube  G,  and  issues  into  the  atmosphere  in  a  continuous 
stream,  carrying  with  it  any  air  mixed  with  the  exhaust  steam,  the 
action  being  somewhat  similar  to  that  of  the  injector  for  feeding 
boilers. 

It  is  requisite  for  the  injection  water  to  enter  the  combining 
nozzle  in  a  straight  stream,  without  any  eddy  or  rotation  of  the 
water;  and  whenever  the  injection  is  supplied  with  the  pressure  of 
a  head  of  lO  feet  or  upwards,  a  provision  is  made  for  stopping  any 
rotation  of  the  stream,  by  inserting  within  the  nozzle  a  guiding  piece 
R,  with  several  straight  radial  vanes,  as  shown  in  Fig.  iii. 

The  proportion  that  has  been  found  most  effective  for  the  injec- 
tion jet  is  for  the  length  of  the  free  portion  of  the  jet,  which  is 
exposed  to  the  action  of  the  exhaust  steam,  to  be  about  three  times 
the  diameter  of  the  jet,  except  when  the  injection  water  is  supplied 
with  a  head  of  lO  feet  and  upwards,  in  which  case  the  length  of  the 
exposed  jet  is  increased  with  advantage  to  3^  diameters. 

The  moving  force  in  the  current  of  the  exhaust  steam  rushing 
into  the  condenser  communicates  an  additional  velocity  to  the 
water  jet  on  issuing  from  the  water  nozzle,  the  amount  of  this 
addition  being  dependent  upon  the  difference  of  pressure  between 
the  exhaust  steam  and  the  condenser;  and  when  the  steam  is  not 
expanded  down  in  the  cylinder  of  the  engine  to  a  very  low  pressure 
before  its  exhaust,  the  combined  moving  force  in  the  water  jet  is 
found  to  be  sufficient  to  effect  a  continuous  discharge  into  the 
atmosphere,  not  only  without  aid  from  a  head  of  water  in  the  injec- 
tion supply,  but  leaving  a  surplus  power  sufficient  for  raising  the  injec- 
tion water  from  a  lower  level  of  several  feet  below  the  condenser. 
When  the  injection  water  is  not  supplied  by  a  head  pressure,  but  has 
to  be  raised  from  a  lower  level,  the  working  of  the  condenser  (Fig.  1 1 2) 
is  started  in  the  first  instance  by  means  of  a  jet  of  steam  direct  from 
the  boiler,  introduced  through  the  central  spindle  C,  so  as  to  act  in 
the  axis  of  the  water  jet.  The  steam  is  admitted  to  this  jet  through 
the  small  piston  valve  J,  which  has  a  second  piston  valve  I,  fixed 
below  on  the  same  spindle.  This  lower  piston  is  supported  by  a 
spiral  spring,  and  communicates  with  the  condenser  on  the  under 
side  by  the  pipe  H;  and  as  soon  as  a  vacuum  is  formed  in  the 
condenser,  the  piston  valve  is  moved,  the  pressure  of  the  atmosphere 
acting  on  the  top  of  the  upper  piston  j  causing  this  piston  to  shut 


STATIONARY   ENGINES. 


179 


off  the  steam  jet.  In  the  event  of  the  vacuum  ever  becoming 
impaired  from  any  cause,  the  piston  valve  is  instantly  raised  by  the 
pressure  of  the  spring  below  it, 
and  a  jet  of  steam  from  the  boiler 
is  thus  applied  by  self-acting 
means  to  the  extent  that  may 
be  required  for  restoring  the  full 
action  of  the  condenser. 

When  the  piston  of  the  engine 
makes  only  a  few  strokes  per 
minute,  the  impulse  received  from 
the  successive  discharges  of  the 
exhaust  steam  fluctuates,  a  por- 
tion of  the  water  fails  to  get  the 
full  velocity  of  discharge  imparted 
to  it,  and  escapes  at  the  nozzle 
into  the  chamber  K.  This  over- 
flow water  is  removed  continu- 
ously by  means  of  the  side  return 
passage  L,  which  communicates 
with  an  annular  space  surround- 
ing the  water  nozzle  A,  and 
the  water  is  carried  forward  by 
being  brought  again  into  con- 
tact with  the  jet  of  exhaust 
steam. 

In  another  form  (Fig.  113)  the 
condenser  is  shown  as  applied  to 
a  pair  of  engines  coupled  at  right 
angles ;  the  only  alteration  being 

the  addition  of  a  second  combining  nozzle  N,  fixed  beyond  the  first 
one,  and  communicating  with  a  second  branch  pipe  M,  which  brings 
the  exhaust  from  the  other  cylinder  of  the  coupled  engines.  The  first 
nozzle  F  so  completely  separates  the  two  steam  jets  from  each  other 
that  the  alternate  discharge  of  the  exhaust  steam  from  either  cylin- 
der cannot  in  any  way  impair  the  vacuum  in  the  other  cylinder: 
the  degree  of  vacuum  is  found  in  some  cases  to  be  rather  higher 
in  the  upper  nozzle  than  in  the  lower  one,  the  steam  in  the  upper 
nozzle  being  the  first  to  come  in  contact  with  the  injection  water. 
In  this  arrangement,  as  well  as  in  the  preceding  one,  a  foot  valve  P 


Fig.  H2. 


-Condenser  with  Self-adjusting  Jet  of 
Steam. 


i8o 


MODERN   STEAM   PRACTICE. 


is  provided  at  the  exit  orifice  of  the  discharge  tube  to  prevent  any 
inflow  of  water  from  the  hot  well  into  the  condenser,  when  the 


vacuum  ceases  when  the  engine  is 
stopped. 

Mr.  Alex.  Morton  of  Glasgow  in- 
forms us  that  he  has  fitted  these  con- 
densers to  all  classes  of  land  en- 
gines, from  the  slow-going  pumping 
engine  making  three  revolutions 
per  minute,  to  other  engines  hav- 
ing a  piston  speed  of  500  feet  per 
minute,  and  even  engines  having 
a  greater  piston  speed  than  this 
have  been  fitted  with  ejector  con- 
densers. 

We  give  side  and  end  views  of 
an  ordinary  horizontal  pumping 
engine  (Figs.  114,  115)  fitted  with 
the  condensing  apparatus.  The  con- 
denser is  placed  below  the  level  of 
the  steam  cylinder  of  the  engine,  and 
may  be  in  any  convenient  position 
either  inside  or  outside  of  the  en- 
gine house.  The  rising  main  from 
the  pit  pumps  delivers  the  water 
into  a  tank  a  few  feet  above  the  level 
of  the  condenser;  having  a  pipe  for 
supplying  the  injection  water  to 
the  condenser,  and  the  discharge 
from  the  condenser  passes  through 
a  pipe  into  a  drain,  as  shown. 

In  another  example  of  blow- 
ing engine  at  an  iron-works  near 
Bridgend  in  Glamorganshire,  the  cylinder  being  40  inches  diameter 
and  10  feet  stroke  of  the  piston,  making  fifteen  revolutions  per 
minute,  the  condensing  apparatus  maintains  a  constant  and  steady 
vacuum  of  12^  lbs.  below  the  atmosphere.  The  injection  water  in 
this  case  is  supplied  from  a  head  of  i  )^  foot  above  the  condenser, 
and  the  discharged  water  has  a  fall  of  about  9  feet,  consequently 


Fig.  113. — Condenser  for  a  pair  of  Coupled 
Engines. 


no  starting  jet  is  required  in  such  cases. 


STATIONARY   ENGINES.  l8l 

The  cold-water  pump  is  a  cast-iron  barrel,  fitted  at  the  bottom 


with  a  suction  valve  of  the  flap  type,  consisting  of  a  disc  of  leather 
securely  fastened  down  with  a  bar  of  iron  to  the  conical  valve  seat, 


1 82  MODERN   STEAM   PRACTICE. 

and  arranged  with  a  central  feather,  the  disc  being  fitted  withwrought- 
iron  plates  on  the  top  and  bottom,  securely  rivetted  through  and 
through.  The  bucket  is  fitted  with  a  valve  of  a  similar  description, 
having  means  of  securing  it  to  the  pump  rod;  and  it  is  usually 
packed  with  a  plain  hemp  gasket  let  into  the  recess  formed  in  the 
bucket,  and  fastened  by  means  of  plain  wooden  pins  driven  through 
holes  bored  in  the  side.  Some  consider,  however,  that  these  buckets 
should  be  fitted  with  gutta-percha  rings,  let  into  recesses  formed  on 
the  bucket,  with  holes  bored  from  the  top  in  connection  with  the 
recesses;  thus  when  the  gutta-percha  rings  are  cut  and  sprung  into 
the  recesses,  the  head  of  water  acts  on  the  inside  of  the  rings,  keeping 
them  up  to  the  face. 

The  feed  pump  is  of  the  ordinary  plunger  type,  fitted  with 
metallic  valves,  and  draws  the  water  from  the  hot  well  above  the 
air  pump,  the  water  being  partially  heated  by  the  steam  in  the 
process  of  condensation.  All  these  pumps  are  generally  worked 
from  rods  directly  fastened  to  the  engine  beam,  on  the  opposite 
end  from  that  of  the  steam  cylinder.  The  rod  for  the  air  pump 
is  generally  placed  midway  between  the  main  centre  and  the  end 
of  the  beam;  the  cold-water  pump  rod  is  situated  between  the 
air-pump  rod  and  the  end  of  the  beam;  while  the  feed-pump  rod 
has  a  shorter  stroke  than  either,  being  placed  between  the  air  pump 
and  the  main  centre  on  which  the  beam  vibrates. 

The  beam  is  generally  shorter  on  the  pump  end,  the  steam  piston 
having  a  longer  stroke;  thus  the  motion  of  the  main  plungers  or 
buckets,  if  so  fitted,  is  slower  than  that  of  the  steam  piston,  and  this 
diminution  of  velocity  decreases  the  wear  and  tear  of  the  pump 
gear.  Moreover,  increased  length  of  piston  stroke  requires  less 
diameter  of  cylinder,  which  is  a  great  desideratum  when  high  steam 
pressure  with  a  large  measure  of  expansion  is  used,  as  the  parts 
need  not  in  this  case  be  made  so  heavy.  Some  makers  have  intro- 
duced a  small  high-pressure  cylinder  in  combination  with  a  larger 
one;  the  steam  in  the  first  place  acts  on  the  small  piston,  and  then 
expands  into  the  large  cylinder.  The  large  cylinder  and  its  adjuncts 
need  not  therefore  be  so  heavy  as  with  the  single-cylinder  arrange- 
ment, but  it  is  obvious  that  greater  complication  is  entailed,  and  for 
economy  of  fuel  the  single  cylinder  with  a  long  piston  stroke  is  to 
be  preferred.  Cornish  engineers  endeavour  to  economize  fuel  by  a 
careful  clothing  of  the  parts  where  radiation  takes  place.  The 
cylinder  is  inclosed  in  a  steam  jacket,  as  already  described;   the 


STATIONARY   ENGINES.  1 83 

outside  cylinder  or  casing  is  covered  over  with  felt  or  non-conducting 
material,  and  then  carefully  lagged  with  wood,  with  four  or  more 
metallic  straps  girding  it  all  round;  in  some  instances  heated  air 
has  been  applied  all  round  the  steam  cylinder,  the  annular  space 
being  encircled  with  brick-work.  The  thorough  protection  of  the 
inside  or  working  cylinder  so  as  to  prevent  surface  condensation, 
and  the  covering  of  the  steam  pipes  from  the  boiler  with  felt  and 
canvas  to  prevent  radiation — combined  with  the  high  steam  pressure 
used  and  the  large  measure  of  expansion  obtained — have  raised 
the  duty  performed  by  the  Cornish  engine  far  above  that  of  the 
ordinary  class  of  engine  used  for  land  purposes. 

Figs.  1 16  and  1 17  give  side  and  end  elevations  of  an  overhead-beam 
pumping  engine  erected  at  a  pit  near  Kilmarnock.  The  principal 
advantage  in  the  arrangement  here  is  that  it  leaves  the  pit  mouth 
clear,  and  in  sinking  a  pit  enables  the  rods  to  be  easily  lengthened 
as  required. 

The  cylinder  is  84  inches  in  diameter,  suited  for  a  12-feet  stroke 
in  the  pump.  The  piston  rod  is  connected  to  a  strong  malleable- 
iron  beam,  made  of  two  plates  placed  15  inches  apart.  The  pump 
rod  is  connected  to  one  end  of  the  beam,  and  the  other  end  is  sup- 
ported by  vibrating  columns  oscillating  on  journals  working  in  two 
bearings,  which  are  bedded  on  the  top  of  the  stone  pedestals  for  the 
foundation,  and  secured  with  bolts  and  nuts  passing  down  through 
the  foundation,  and  having  a  cotter  and  wall  plate  at  the  bottom. 

The  parallel  motion  for  the  piston  rod  consists  of  two  motion 
rods,  one  on  each  side  of  the  beam,  connected  to  cast-iron  standards 
bolted  to  projecting  flanges  on  the  top  of  the  cylinder.  The  plug 
rod  for  the  valve  mechanism  is  worked  directly  off  the  beam,  from 
the  same  gudgeon  as  for  the  parallel-motion  bars,  and  is  guided 
with  a  bracket  placed  underneath  the  engine-room  floor. 

The  engine  is  fitted  with  a  blow-through  condenser,  on  a  plan 
which  works  as  follows: — Steam  being  admitted  to  the  bottom 
of  the  cylinder,  the  piston  is  forced  to  the  top  of  its  stroke;  the 
steam  valve  is  then  shut  by  suitable  gearing,  and  the  stearu 
passes  from  the  bottom  side  of  the  cylinder  to  the  top  side,  the 
piston  is  then  in  equilibrium,  and  the  weight  of  the  pump  rods 
carries  it  to  the  bottom,  but  before  it  reaches  this  point  the  injector 
valve  is  opened  with  a  tappet  placed  on  the  feed-pump  rod,  with 
levers  and  rod  carried  along  to  the  valve;  water  is  thus  admitted 
into  the  condenser,  and  the  valve  remains  open  until  the.  steam  is 


1 84 


MODERN   STEAM   PRACTICE. 


shut  off,  and  the  piston   nearly  at  the  end  of  the  up  stroke;  the 
remauiing-  exhaust  steam  in  the  top  blows  the  water  and  condensed 


Fig.  1 16. ^-Overhead-beam  Pumping  Engine.     Side  Elevation. 

Steam  out  of  the  blow-through  valves  at  the  bottom  of  the  condenser 
into  the  overflow  cistern,  from  which  it  is  led  into  a  drain.  In 
working,  the  water  in  the  condenser  rises  to  nearly  the  level  of  the 


STATIONARY   ENGINES. 


185 


injection  valve.     Besides  the  ordinary  steam  and  exhaust  valves, 
there  is  a  valve  worked  by  hand  for  regulating  the  descent  of  the 


Fig.  117. — Overhead-beam  Pumping  Engine.     End  Elevation. 

piston,  and  placed  at  the  bottom  of  the  passage  leading  to  the  top 
of  the  cylinder.  The  feed  pump  is  of  the  plunger  type,  worked 
directly  off  the  overhead  beam;  the  suction  valve  is  placed  at  the 


186 


MODERN   STEAM    PRACTICE. 


bottom  of  the  barrel,  and  the  deHvery  valve  at  the  top.  The  annular 
space  round  the  plunger  is  equal  to  the  area  of  the  plunger.  With 
this  arrangement  no  air  can  collect  at  the  under  side  of  the  gland, 
as  when  the  delivery  valve  is  placed  at  the  bottom  of  the  barrel. 

The  main  pump  for  this  engine  is  of  the  plunger  type,  the  rods 
being  cottered  to  the  plunger,  instead  of  the  wooden  rod  passing 


Fig.  1 18. —Pump. 

A,  Plunger.       B,  Stuffing  box  and  gland.      C,  Suction  valve,      d,  Deliver}^  valve. 

E,  Stand  pipe  with  air  vessel,     f  Pump  rod. 

down  through  it,  as  has  been  already  explained.  The  diameter  of 
the  plunger  is  18  inches,  with  an  annular  space  all  round  equal  to  the 
area  of  the  rams.  The  suction  and  delivery  valves,  of  the  flap  type, 
are  placed  at  the  top  of  the  pump  barrel — this  arrangement  getting 
rid  of  the  air  that  collects  in  a  barrel  having  the  valves  arranged  at 
the  bottom.  On  the  stand  pipe  an  air  vessel  is  fitted,  to  relieve  the 
shock  on  the  ram  in  the  act  of  forcing  the  water.  This  arrangement  of 


STATIONARY   ENGINES. 


187 


pump  necessitates  the  use  of  a  separate  suction  pipe,  which  is  fitted 
to  the  side  of  the  valve  chest  placed  underneath  the  suction  valve. 

Side-lever  engines  have  been  introduced  with  the  object  of  re- 
ducing the  great  height  of  the  massive  lever  wall  for  carrying  the 


main  beam,  and  of  simplifying  the  engine  by  dispensing  with  the 
expensive  parallel  motion.  The  arrangement  possesses  certain 
advantages;  the  main  one  being  that  the  engine  is  self-contained, 
having  a  bed  plate  for  carrying  the  cylinder,  main  pillow  blocks, 
condenser,  air  pump,  &c.  The  side  levers  are  connected  to  the 
piston  rod  by  means  of  side  rods,  and  a  crosshead  working  in  cast- 
iron  guide  frames;  the  expense  of  keeping  in  repair  those  guides,  in 


1 88  MODERN   STEAM   PRACTICE. 

comparison  with  the  numerous  brasses  of  the  parallel  motion,  is 
very  trifling.  The  air  pump  is  worked  in  a  similar  manner,  while 
the  plug  rod  is  actuated  with  a  separate  wrought-iron  beam,  placed 
above  the  main  crosshead,  and  worked  therefrom  by  means  of  a 
small  crosshead,  fitted  to  the  top  of  the  piston  rod  with  a  parallel 
motion — an  unnecessary  refinem.ent,  as  when  the  plug  rod  is  guided 
at  the  top  and  bottom  a  plain  link  attachment  is  all  that  is  needed. 


,  Fig.  1 20. — Single-acting  Side-lever  Pumping  Engine. 

The  other  end  of  this  beam  vibrates  on  a  gudgeon,  with  pillow 
blocks  resting  on  the  end  wall  of  the  engine-house.  The  spring 
beams  of  wood  are  placed  on  each  side  of  the  foundation,  these 
springs  being  necessary  to  check  the  shock  should  the  engine  miss 
a  stroke  or  come  in  or  out  too  rapidly — the  ends  of  the  side  levers, 
striking  against  the  spring  beams,  greatly  reduce  the  blow,  which 
would  otherwise  be  felt  very  severely  on  the  machinery. 

There  is  another  example  of  the  side -lever  pumping  engine.  Fig. 
120,  which  although  not  possessing  tlie  advantage  of  being  securely 


STATIONARY   ENGINES.  1 89 

bedded  on  a  base  plate,  yet  reduces  the  height  of  the  lever  wall 
considerably,  while  its  arrangement  is  somewhat  simpler  than  in  the 
foregoing  example.  The  valve  gear  is  placed  between  the  cylinder 
and  the  main  centre  of  the  side  levers;  thus  the  additional  beam 
for  working  the  plug  rod  is  dispensed  with,  the  rod  being  worked 
directly  from  a  cross  gudgeon  between  the  two  side  levers;  this 
gudgeon  has  an  elongated  hole  for  the  rod  to  pass  through,  and  is 
fitted  with  two  side  links  connected  to  a  crosshead  on  the  plug  rod, 
the  rod  being  guided  through  bushes  at  the  top  and  bottom.  All 
the  other  pumps  are  worked  directly  from  a  gudgeon  placed  between 
the  side  levers,  and  securely  keyed  to  them;  but  the  main  pump 
gudgeon  has  a  bearing  at  each  end,  working  on  turned  bushes  on 
the  under  side.  This  gudgeon  is  made  flat  in  the  body,  being 
deeper  at  the  middle,  and  the  pump  rods  of  wood  are  securely 
fastened  to  it  by  means  of  wrought-iron  straps,  the  great  length  of 
the  pump  rods  causing  them  to  bend  with  the  versed  sine  described 
by, the  side  levers.  The  pillow  blocks  for  carrying  the  side  levers 
are  provided  with  a  broad  base  plate,  securely  bolted  down  to  the 
lever  wall;  the  caps  for  the  pillow  blocks  are  simply  shells,  fitted  for 
the  sake  of  appearance,  as  indeed  are  all  the  covers  for  the  pillow 
blocks  of  Cornish  engines  when  adapted  for  mining  purposes.  This 
arrangement  is  adopted  owing  to  the  steam  acting  on  the  top  of  the 
piston  at  one  end  of  the  beam,  while  the  great  weight  jf  the  pump 
rods  is  being  lifted  at  its  other  end;  and  in  the  outgoing  stroke,  or 
descent  of  the  pump  rods,  the  steam  pressure  on  the  top  of  the 
piston  is  in  excess  of  the  under  side,  and  consequently  the  side 
levers  have  no  tendency  to  lift. 

Some  mine-pumping  engines  have  been  erected  on  the  direct- 
action  principle,  the  steam  cylinder  being  placed  directly  over  the 
pumping  shaft,  with  the  pump  rods  attached  directly  to  the  piston 
rod,  the  steam  acting  on  the  under  side  of  the  piston.  There  is  no 
equilibrium  valve  fitted  to  this  class,  as  the  steam,  after  doing  duty 
in  lifting  the  pump  rods,  is  exhausted  into  the  condenser,  which  is 
in  connection  with  the  top  of  the  cylinder,  and  the  downward 
motion  of  the  pump  rods  is  retarded.  The  weight  of  these  rods  is 
always  in  excess  of  what  is  required  for  forcing  the  water,  and  is 
due  to  the  diameter  of  the  pump  and  the  great  length  of  the  rods. 
Of  course  the  steam  in  the  cylinder  can  be  throttled  in  its  passage 
to  the  condenser,  thus  gradually  reducing  the  pressure  and  prevent- 
ing the  pump  rods  descending  too  rapidly.     The  air  pump  is  worked 


1 90  MODERN   STEAM   PRACTICE. 

by  a  vibrating  lever,  linked  to  the  piston  rod,  and  placed  underneath 


Fig.  121. — Direct-acting  Pumping  Engine.     Side  Elevation. 


ip 
I 


i 

the  cylinder  floor;  the  motion  of  the  lever  working  the  plug  rod  for 
the  valve  mechanism.     This  class  of  engine,  modified,  has  come 


STATIONARY   ENGINES.  I9I 

into  extensive  use,  and,  although  cheaper  in  first  cost,  we  unhesi- 


Fig.  122. — Direct-acting  Pumping  Engine.     End  Elevation. 

tatingly  give  the  preference  to  the  beam  engine,  or  the  more 
recent  example  the  side-lever  Cornish  engine,  when  the  depth  of 
the  mine  is  considerable. 

Figs.  121  and  122  show  side  and  end  elevations  of  a  pit  engine 
which  may  be  considered  an  improvement  on  the  foregoing 
example.      The    steam    cylinder   has    a   diameter   of    84    inches, 


192  MODERN   STEAM   PRACTICE. 

suited  for  a  13-feet  stroke.  The  pump  rods  are  connected  directly 
to  the  piston  rod,  which  is  guided  by  means  of  a  crosshead  and  cast- 
iron  guides  placed  underneath  the  cyhnder.  The  light  wrought-iron 
beam  for  working  the  plug  rod,  air  pump,  and  feed  pump  is  placed 
overhead,  and  is  worked  from  a  continuation  of  the  piston  rod.  The 
vertical  motion  of  the  plug  rod  is  maintained  by  means  of  motion 
rods  fitted  on  each  side  of  the  beam,  and  is  guided  with  a  bracket 
bolted  to  the  nozzle  chest;  the  other  end  of  the  beam  slides  in  cast- 
iron  guide  bars,  with  gudgeon  and  sliding  blocks  fitted  to  it.  The 
air  pump  is  placed  centrally  with  the  condenser,  and  is  worked  off 
a  continuation  of  the  plug  rod;  the  air-pump  bucket  foot  and  head 
valves  are  fitted  with  small  disc  india-rubber  valves,  with  guards 
secured  by  a  single  stud  bolt  in  each.  The  feed  pump  has  a  hollow 
plunger,  and  is  worked  off"  the  overhead  beam  directly,  the  pump 
being  bolted  to  the  side  of  the  hot  well.  This  engine  goes  far  to 
meet  the  requirements  of  the  practical  miner,  being  well  arranged, 
with  easy  access  to  all  the  parts;  and  it  is  much  cheaper  in  first  cost 
than  some  other  beam  engines. 

The  pumps  for  this  engine  consist  of  two  lifting  sets  20  inches 
in  diameter,  and  one  forcing  set  26  inches  in  diameter,  placed  one 
above  the  other,  as  shown  in  Fig.  123.  In  deep  pits  this  plan  is 
always  adopted,  the  lifting  sets  placed  at  the  bottom  of  the  pit 
discharging  into  a  cistern  from  which  the  forcing  set  draws  its 
supply.  By  this  means  the  bucket  and  clack  of  the  lifting  set  can 
be  withdrawn  and  replaced  should  anything  go  wrong,  and  the 
water  rise  above  the  valve  chests,  which  could  not  be  done  were  the 
forcing  set  placed  at  the  bottom  of  the  pit.  The  pump  valves  are 
of  the  ordinary  description,  with  inclined  seatings;  the  plunger  of 
the  forcing  set  has  just  the  necessary  clearance  in  the  barrel,  the 
valve  chests  being  arranged  at  the  bottom;  the  water  is  discharged 
into  an  air  vessel  surrounding  the  stand  pipe,  by  which  means  the 
shock  in  forcing  it  up  is  greatly  softened. 

For  very  deep  pits  a  series  of  lifts  is  necessary.  The  following 
example  (Figs.  124  and  125)  of  pit  work  in  Cornwall  forms  a  good 
arrangement:  "The  diameter  of  the  steam  cylinder  is  90  inches. 
The  stroke  is  1 1  in  and  10  out,  in  miners'  parlance;  that  is  to  say, 
II  feet  in  the  cylinder  and  10  feet  in  the  pumps.  The  first  lift  of 
pumps  from  surface,  or  'grass,'  is  the  house  lift,  which  is  employed  in 
lifting  water  from  the  adit  to  the  condensing  cistern  of  the  engine. 
The  plunger  of  this  lift  is  12  inches  in  diameter,  and  the  rising  main  the 


STATIONARY   ENGINES. 


193 


same  size;  it  is  usual  to  make  the  '  pumps'  or  rising  main  the  same 
size  as  the  plunger.     The  adit  is  31  fathoms  below  the  surface,  and 


Fig.  123. — Pumps  for  Direct-acting  Engine. 
A,  Forcing  set.     B  b.  Lifting  sets,     c.  Stand  pipe  with  air  vessel. 

conducts  the  water  delivered  from  the  pumps  into  the  adjoining 
valley.  Of  course  it  is  an  advantage  to  have  the  adit  as  deep  as 
possible,  that  the  engine  may  have  the  minimum  amount  of  work 

13 


194 


MODERN   STEAM   PRACTICE. 


to  do.  The  second  lift  is  situated  47  fathoms  under  the  adit,  and 
is  provided  with  two  suction  and  two  dehvery  clacks.  The  third 
lift  is  80  fathoms  under  adit;  the  fourth  120  fathoms,  and  the  draw- 
ing lift  140  fathoms.     It  is  not  advisable  to  put  in  a  lift  of  pumps 


Fig.  124. — Pit  Work,  showing  Pumps,  Rods,  Cisterns,  &c. 

with  ordinary  valves  more  than  40  fathoms  long,  because  the  valves 
will  not  stand  the  wear  and  tear  consequent  on  the  great  pressure 
of  the  column  of  water.     For  ordinary  use  the  clack  valve  with 


STATIONARY   ENGINES. 


195 


leather  seats  enjoys  the  greatest  favour  in  Cornwall.  The  pole  case, 
that  is,  the  case  into  which  the  plunger  enters,  is  placed  on  one  leg 
of  what  is  termed  the  H-piece.     The  H-piece  is  provided  with  a 


Fig.  125. — Pit  Work,  showing  Pumps,  Rods,  Cisterns,  &c. 

door  or  cover,  through  which  the  suction  valve  may  be  examined. 
The  seating  of  the  valve  is  made  conical  on  the  outside,  and  is 
somewhat  smaller  than  the  conical  neck  formed  to  receive  it  in  the 


195  •  MODERN   STEAM   PRACTICE. 

H-piece.  Around  the  seating  is  wrapped  a  strip  of  coarse  flannel 
or  baize,  which  makes  the  joint  when  the  seating  is  forced  into  its 
place.  Above  the  door  of  the  H-piece  is  placed  the  door  piece, 
which  contains  the  delivery  valve,  which  is  fixed  in  the  same  way  as 
the  suction  valve.  On  the  door  piece  the  pumps  or  rising  main,  in 
9-feet  lengths,  are  placed.  It  is  usual  to  place  a  wind  bore  directly 
under  the  H-piece,  leading  into  a  cistern  from  which  the  pump  takes 
its  water,  but  in  the  example  under  notice  a  much  better  arrange- 
ment has  been  adopted.  The  cistern  is  placed  just  above  the 
suction  valve,  so  that  the  water  may  more  readily  follow  up  the 
plunger,  and  thereby  cause  the  pump  to  be  'charged  solid.'  It  is 
of  very  great  importance  that  no  vacant  space  whatever  should  be 
left  in  the  pumps  at  the  termination  of  the  indoor  stroke  of  the 
engine,  for  if  there  be  a  space  not  occupied  with  water,  then  a  shock 
ensues,  and  the  engine  works  as  if  working  in  '  fork,'  or  as  if  the 
pumps  were  taking  air.  A  6-inch  branch  and  blank  cover  is  pro- 
vided in  the  U-piece  under  the  H-piece,  for  the  convenience  of 
getting  out  anything  which  may  accidentally  drop  into  it.  A  blank 
end  and  'matching'  piece  is  put  on  to  the  H-piece  under  the  pole 
case,  which  takes  its  bearing  on  the  timber  bearers  below.  The 
main  rods  are  of  Memel  timber,  perfectly  sound  and  straight,  with- 
out knots  or  faults;  for  the  first  50  fathoms  they  are  18  inches 
square,  for  the  next  40  fathoms  16  inches  square,  and  for  the  last 
30  fathoms  14  inches  square.  The  rods  are  obtained  as  long  as 
possible,  and  are  jointed  by  means  of 'strapping  plates,'  bolts,  and 
nuts.  The  timber  is  sometimes  cut  in  the  form  of  a  splice,  and 
made  to  form  a  lap  joint,  but  in  this  case  the  rods  are  all  butt- 
jointed,  the  strapping  plates  are  first  firmly  secured  to  the  piece  to 
be  attached,  and  then  the  piece  is  put  in  its  place  on  the  main  rods, 
the  joint  being  brought  up  tight  by  powerful  lifting  jacks.  The 
main  rods  are  kept  in  a  line  by  means  of  wood  guides  fixed  at 
intervals.  The  plungers  are  cast  with  a  plain  core  through  them, 
and  a  little  longer  than  is  necessary  for  the  stroke;  the  casting 
should  be  entirely  free  from  specks — it  is  usual  to  cast  them  on  the 
side,  but  we  prefer  to  have  them  cast  on  end.  The  plunger  is 
'stocked'  on  the  mine;  a  piece  of  Memel  timber,  square  in  section, 
and  equal  in  diameter  to  the  plunger,  is  obtained,  about  12  feet 
or  14  feet  longer  than  the  '  pole.'  For  a  portion  of  its  length  equal 
to  that  of  the  pole  it  is  rounded  down,  and  the  pole  is  then  forced 
on  to  it.     When  stocked  it  is  fixed  by  means  of  staples  and  glands 


STATIONARY   ENGINES.  1 97 

to  the  main  rods,  a  set  off,  or  filling  piece,  being  provided  between 
the  stock  of  the  pole  and  the  main  rod,  to  bring  the  axis  of  the  pole 
in  a  line  with  that  of  the  pole  case.  Key-ways  should  be  provided 
in  the  joint  between  the  stock  and  set  off,  and  also  between  the  set 
off  and  main  rod;  when  the  staples  and  glands  are  firmly  secured, 
the  keys — of  hard  wood — should  be  driven.  It  requires  great  care 
that  the  'pole  connection'  may  be  well  made.  Square  nuts  should 
always  be  used  for  the  pit  work,  because  it  is  not  always  convenient 
to  have  snugly-fitting  spanners,  and  square  nuts  are  then  more 
easily  managed  than  others.  The  stuffing  box  of  the  pole  case 
should  be  packed  with  a  well-made  gasket  and  tallow. 

"The  working  barrel  of  the  'drawing  lift'  is  bored  a  little  taper 
for  9  inches  or  i  foot  at  the  upper  end,  that  the  bucket  may  easily 
enter  when  dropped  in  from  above;  sometimes  a  door  piece  is  pro- 
vided above  the  working  barrel,  that  the  bucket  may  be  examined 
without  the  necessity  of  drawing  it;  but  the  plan  is  not  a  good  one 
when  forking,  as  the  water  may  rise  too  fast,  and  if  it  gets  above 
the  door  before  the  joint  can  be  properly  made  the  consequence 
becomes  serious.  Directly  under  the  working  barrel  is  placed  the 
'  buU's-head,'  which  is,  in  fact,  a  supplementary  valve  box,  available 
when  the  'door  piece'  is  under  water.  The  neck  of  the  bull's  head 
should  be  bored  conical,  and  the  valve  seating  geared  similarly  to 
an  ordinary  bucket,  but  the  ring  should  be  a  little  conical,  that  it 
may  be  prevented  from  falling  through  the  neck  of  the  bull's  head 
and  retained  in  its  place.  A  wrought-iron  loop  or  staple  is  provided 
on  the  seating,  by  means  of  which  it  may  be  fished  up  from  above 
when  occasion  requires.  A  small  bar  is  placed  across  the  staple, 
which  acts  as  a  guard  to  the  clack  valve.  The  ring  of  the  bucket 
should  be  of  wrought  iron,  nearly  the  size  of  the  barrel,  parallel  on 
its  outer  face  and  conical  within.  For  the  convenience  of  removing 
the  doors  and  replacing  them  again  a  chain  with  swivel  and  screw 
is  sometimes  used,  suspended  from  a  piece  of  timber  above.  For 
the  facility  of  sinking,  under  the  suction  valve  is  suspended  a 
turned  pipe  which  enters  a  stuffing  box  placed  above  the  wind  bore. 
The  wind  bore  is  suspended  in  chains  provided  with  lifting  screws, 
for  the  convenience  of  lowering  as  sinking  proceeds.  It  will  be 
seen  that  as  sinking  proceeds  it  becomes  necessary  to  lower  the 
drawing  lift  constantly,  and  that  it  may  be  conveniently  done  the 
pumps  are  suspended  in  'yokes'  which  take  their  bearings  on  tim- 
bers fixed  across  the  shaft.     Yokes  are  glands  made  to  fit  the  body 


198  MODERN    STEAM   PRACTICE. 

of  the  pump;  they  are  placed  directly  under  the  ribs,  and  when  it 
is  required  to  lower  the  lift  the  yokes  are  loosened  to  let  the  lift 
drop  through.  Each  time  there  is  a  new  length  or  pump  put  in, 
the  bucket  has  to  be  lowered,  and  that  it  may  be  done  without  the 
necessity  of  making  a  new  drawing  lift  connection  on  the  main  rods, 
the  arrangement  shown  in  Fig.  125  is  introduced;  a  chain  and  hook 
serves  to  make  the  connection  between  the  main  rods  and  the  pump 
rod,  one  staple  only  being  used  to  steady  the  top  of  the  pump  rod. 
This  arrangement  affords  facilities  both  for  drawing  the  bucket 
and  putting  in  a  new  pump.  The  pump  joints  are  made  with  flat 
rings  of  wrought  iron,  covered  with  baize  and  dipped  in  tar. 

"  Balance  bobs  are  sometimes  placed  below  the  surface  to  take  up 
some  of  the  weight  of  the  pump  rods.  The  connection  with  the 
main  rods  is  usually  of  wood;  the  vibration  is  given  by  the  elasticity 
of  the  wood.  In  the  example  shown  in  Figs.  124,  125,  the  connecting 
rod  is  15  fathoms  long,  and  it  is  guided  and  steadied  by  means  of 
a  plain  turned  pulley,  which  bears  against  a  curved  filling  piece 
bolted  on  to  the  connecting  rod.  Plungers  are  sometimes  substituted 
for  balance  bobs,  and  are,  when  so  employed,  constantly  submitted 
to  the  pressure  of  the  column  of  water  in  the  pumps;  they  are  fixed 
to  the  main  rods  precisely  in  the  same  way  as  the  ordinary  plunger."^ 

With  the  view  of  securing  greater  regularity  in  the  motion, 
and  of  equalizing  the  strain  on  the  various  parts,  the  compound 
or  double-acting  engine  has  been  introduced.  An  example  of 
this  engine  is  shown  in  Fig.  126.  The  high-pressure  cylinder  is 
36  inches  in  diameter,  and  the  low-pressure  cylinder  54  inches 
in  diameter,  both  working  an  8-feet  stroke  in  the  pumps.  The 
piston  rod  of  each  cylinder  is  coupled  directly  to  the  pump  rods, 
and  from  the  crosshead  of  each  piston  rod  run  two  short  connect- 
ing rods,  attached  to  two  bell  cranks;  these  cranks  are  connected 
to  each  other  at  the  top  by  the  connecting  rods  on  each  side,  thus 
coupling  the  two  engines  and  equalizing  their  duty.  From  the 
longitudinal  centre  of  one  of  the  bell  cranks  the  motion  for  the 
tappet  rod  is  taken,  and  from  the  back  of  the  other  one ;  an  arm  is 
cast  on  each,  with  connecting  rods  for  taking  the  crosshead  for  the 
air  pump.  The  cylinders,  with  their  covers  and  ends,  are  steam- 
jacketed,  and  securely  bolted  down  to  a  bed  plate  resting  on  foun- 
dations of  stone.  The  cast-iron  guides  for  the  piston-rod  crosshead 
are  bolted  to  the  under  side  of  the  bed  plate,  and  the  bottom  end  is 

^  The  Engineer, 


STATIONARY   ENGINES. 


199 


secured  to  the  cast-iron  beams  upon  which  the  bell-crank  pillow 
blocks  and  air  pump  and  condenser  are  fitted.  The  air  pump  is  of 
the  ordinary  kind,  fitted  with  india-rubber  valves  for  bucket,  head, 
and  foot  valves.    The  condenser  is  a  separate  vessel  placed  alongside 


Fig.  126. — Direct-action  Compound  Pumping  Engine. 

of  the  air  pump,  the  waste-steam  pipe  coming  in  at  the  top,  and 
fitted  with  a  packed  gland.  The  valve  gear  for  these  engines  is  of 
the  usual  description,  with  cataract  pumps  for  regulating  the  number 
of  strokes.  Although  the  machinery  in  these  engines  is  rather  com- 
plicated, yet  when  economy  in  fuel  and  great  regularity  in  working 


coo  MODERN   STEAM   PRACTICE. 

have  to  be  studied,  they  may  be  beneficially  used  for  pumping  water 
from  moderate  depths  and  forcing  or  lifting  it  to  moderate  heights. 

For  moderate  depths  horizontal  high-pressure  pumping  engines 
have  been  used,  connected  to  two  bell  cranks,  directly  from  the  piston- 
rod  crosshead,  with  long  links,  one  on  each  side,  taking  the  long 
arm  of  the  bell  crank  nearest  the  engine;  and  the  two  bell 
cranks  are  connected  to  each  other  with  wooden  connecting  links 
strapped  with  wrought  iron,  the  pins  for  carrying  these  links 
being  nearer  the  centre  of  vibration  of  the  bell  cranks;  thus  the 
stroke  of  the  engine  is  somewhat  longer  than  that  of  the  pumps. 
The  bell  cranks  are  so  arranged  that  the  one  goes  up  and  the 
other  down  alternately,  the  steam  being  admitted  into  each  end 
of  the  cylinder  as  in  ordinary  high-pressure  engines.  The  valve 
mechanism  is  worked  in  a  similar  manner  to  that  of  the  Cornish 
engine,  with  tappets,  cataracts,  and  all  the  necessary  starting  handles. 
One  useful  feature  in  this  class  of  engine  is  that  it  can  be  driven  at 
a  higher  or  lower  rate  of  speed,  or  more  or  fewer  strokes  given,  as 
the  increased  or  diminished  quantity  of  water  in  the  pit  may  require. 
The  exhaust  steam  is  made  to  pass  through  a  series  of  tubes,  around 
which  there  is  a  constant  circulation  of  cold  water;  thus  the  steam 
is  partially  condensed,  and  the  water  pumped  into  the  boilers  again, 
as  in  surface-condensing  engines,  A  jet  of  steam,  however,  escapes 
into  the  atmosphere  at  each  stroke,  which  is  due  to  the  tube  surface 
not  being  of  sufficient  area,  and  to  give  the  condensing  vessel  the 
requisite  area  would  make  it  too  bulky  and  expensive.  By  this 
method  of  allowing  the  exhaust  steam  to  pass  through  the  tubes 
the  water  around  them  is  heated  to  a  high  degree,  and  it  can  be 
pumped  into  the  boiler  separately,  or  mixed  with  the  water  collecting 
in  the  receiver;  but  in  either  case  the  tube  surface  acts  as  a  feed- 
water  heater. 

Horizontal  high-pressure  engines  with  slide  valves  and  eccentric 
motion  are  sometimes  used  for  pumping  water  out  of  coal  and  other 
mines.  The  valve  gear  is  of  the  simplest  description,  consisting  of 
a  rocking  lever,  fitted  with  a  link  for  the  valve  rod,  and  a  pin  for 
taking  the  gab  end  on  the  eccentric  rod,  which  is  made  to  throw 
out  of  gear  when  required.  The  cylinder  is  securely  bolted  to  one 
end  and  the  pillow  block  for  the  crank  shaft  to  the  other  end  of  the 
bed  plate,  which  consists  of  a  heavy  box  casting  placed  on  each 
side  of  the  cylinder,  running  the  entire  length  of  the  foundations, 
and  secured  at  the  ends  with  cross  pieces  all  cast  together,  and 


STATIONARY   ENGINES.  20I 

bedded  on  balks  of  timber,  which  in  some  instances  form  the  founda- 
tion. In  these  engines  a  long  stroke  and  low  rate  of  piston  speed 
are  adopted,  the  motion  for  the  pump  being  as  simple  as  practicable 
to  suit  the  requirements.  The  connecting  rod  is  coupled  to  the  pin 
on  the  crank,  or  cast-iron  disc  when  so  fitted,  by  a  strap  with  jibs 
and  key,  and  the  crosshead  end  has  a  short  fork  forged  on  the 
connecting  rod,  fitted  with  straps,  jibs,  and  keys.  The  crank  shaft 
is  generally  as  short  as  practicable,  and  is  supported  by  a  bearing 
on  the  bed  plate,  and  one  at  the  end  carried  on  a  pillow  block  bolted 
to  a  box  girder  secured  to  the  foundations.  The  fly  wheel  is  made 
heavy,  and  is  placed  at  the  middle  of  the  shaft  between  the  two 
bearings;  and  at  the  extreme  end  a  cast-iron  crank  is  fitted,  with 
holes  for  the  pin  to  vary  the  stroke  of  the  pump  when  required. 
The  motion  for  the  pit  pump  is  transmitted  by  a  wooden  connecting 
rod,  strapped  with  wrought  iron  secured  with  bolts;  the  other  end 
of  the  rod  taking  a  bell  crank  or  arm  fitted  to  the  shaft  on  which 
the  bell  crank  is  placed.  The  latter  can  be  suited  to  any  angle  at 
which  the  pump  may  require  to  be  placed,  as  in  working  the  edge 
coal  in  certain  localities. 

In  other  arrangements,  when  the  pumping  shaft  is  vertical,  the 
motion  for  the  pump  is  taken  from  a  crosshead  fitted  to  a  pro- 
longation of  the  piston  rod,  which  is  continued  through  the  end  of 
the  cylinder;  the  crosshead  is  guided  the  same  as  for  the  main  con- 
necting-rod end,  and  is  connected  to  the  bell  crank  by  wooden  rods 
strapped  with  wrought  iron.  In  such  examples  the  pit  pumps  are 
in  duplicate,  with  a  bell  crank  for  each,  connected  together  in  the 
same  way;  by  this  means  the  engine  is  better  balanced,  as  one  set 
of  pump  rods  is  moving  upward  and  the  other  set  downward.  The 
pillow  blocks  for  the  bell  cranks  are  fitted  to  balks  of  timber,  and 
the  foundation  for  the  engine  is  built  of  brickwork  laid  on  the  top 
of  these  balks,  the  brickwork  being  overlaid  with  timber  for  bedding 
the  engine;  the  bed  plate  is  secured  by  long  bolts  passing  down  to 
the  bottom  of  the  foundation.  There  is  no  feed  pump  connected 
to  these  engines,  a  steam  pump  being  fitted  for  supplying  the  boilers 
with  water. 

There  are  a  variety  of  engines  for  pumping  water  of  the  geared 
description,  working  plain  cranks  connected  to  bell  cranks  by  a 
single  rod,  the  bell  crank  having  a  jaw  cast  on  it,  with  a  pin  for 
taking  the  end  of  the  connecting  rod  passing  through  the  jaws. 
This  type  of  engine  is  generally  adopted  for  low  lifts,  and  is  a  very 


202  MODERN   STEAM   PRACTICE. 

convenient  form  for  transportation,  as  the  cylinder  is  of  small 
diameter,  with  a  high  rate  of  piston  speed,  and  reducing  gear  for 
the  pumps.  When  the  engines  are  of  the  horizontal  type  the  whole 
of  the  wheel  gearing  should  be  arranged  on  the  same  bed  plate 
as  the  engine,  and  kept  as  compact  as  possible,  since  detached 
machinery  cannot  be  so  securely  bolted  down  on  the  foundations 
as  when  all  the  parts  are  well  bonded  together  on  a  single  bed 
plate. 


PUMPING   ENGINES    FOR   WATER-WORKS. 

Having  considered  engines  for  pumping  water  out  of  mines, 
we  now  come  to  that  class  of  Cornish  engine  used  for  pumping 
water  for  the  supply  of  large  towns.  The  construction  of  the 
water-works  engine  differs  materially  from  that  of  ordinary  mine- 
pumping  engines.  It  is  generally  of  the  single-acting  type;  the 
whole  power  of  the  engine  is  employed  to  lift  a  weighted  plunger 
placed  at  the  end  of  the  beam  farthest  from  the  cylinder,  and 
which  acts  as  an  accumulator,  forcing  the  water  up  the  stand  pipes 
to  the  height  required  for  distribution  through  the  mains.  This 
height  of  course  depends  on  the  altitude  of  the  city  or  reservoir 
above  the  source  from  which  the  pumps  draw  the  water.  The 
engine  beam  is  supported  on  columns,  carrying  a  spring  beam  on 
which  the  main  pillow  blocks  are  securely  bolted,  and  the  ends 
are  let  into  and  rest  on  the  end  walls  of  the  engine  house.  The 
perpendicular  motion  of  the  piston  rod  at  the  one  end  of  the  beam 
and  of  the  weighted  plunger  at  the  other  end,  is  effected  by  means 
of  parallel  motion  of  the  ordinary  description,  with  connecting  links 
from  the  crosshead,  radius,  and  parallel  bars.  The  air  pump  is 
worked  off  the  centre  of  the  back  link  for  the  parallel  motion,  at 
the  main  pump  end;  while  the  feed  pump  has  a  shorter  stroke,  being 
connected  by  means  of  a  long  rod  with  a  pin  passing  through  the 
main  beam.  The  plug  rod  for  working  the  tappets  of  the  valve 
gear  is  attached  to  the  beams  in  like  manner,  the  valve  gear  being 
fitted  with  all  the  necessary  cataracts,  as  in  the  mine-pumping  engine. 
An  engine  house  incloses  all  the  machinery  except  the  stand  pipes, 
which  are  of  great  height,  and  require  a  separate  tower.  As  the 
water  in  these  pipes  is  liable  to  become  frozen  in  winter,  objections 


STATIONARY   ENGINES. 


203 


have  been  taken  to  them,  and  as  they  are 
mainly  raised  to  equalize  the  duty  on  the 
engine  some  authorities  consider  a  large  air 
vessel  preferable.  The  pipes  must  be  fitted 
with  a  valve  loaded  to  a  certain  pressure  on  the 
delivery  side,  so  that  in  the  event  of  derange- 
ment from  a  pipe  bursting,  or  from  a  diminu- 
tion of  pressure  in  the  main,  the  engine  would 
still  have  about  the  same  duty  to  perform,  as 
the  water  has  to  be  forced  through  the  passage 
covered  with  the  loaded  valve  before  it  is  taken 
into  the  air  vessel,  a  double-beat  valve  being 
used  for  that  purpose.  This  description  of 
valve  gives  a  large  area  for  the  exit  of  the 
water,  while  the  surface  acted  upon  for  raising 
the  valve  is  only  a  small  portion  of  the  total 
area  of  the  passages ;  thus  less  weight  or  pres- 
sure on  the  top  of  the  valve  is  required.  There 
is  also  a  blow-off  valve  fitted,  and  loaded  to  a 


__^_^^^//^////y/m//my//4//m  ^ 


Fig.  127. — Single-acting  Pumping  Engine  with  Stand-pipe  Tower. 


204  MODERN    STEAM   PRACTICE. 

certain  weight,  so  that  in  the  event  of  any  undue  pressure  in  the 
mains  the  water  escapes,  and  prevents  the  pipes  bursting.  This 
valve  acts  in  a  similar  manner  to  relief  valves  fitted  to  feed  pumps 
for  steam  boilers,  the  water  escaping  into  the  well  or  reservoir  from 
which  it  is  drawn. 

Double-cylinder  expansion  engines  have  been  successfully  adopted 
for  water- works;  where  a  high  rate  of  expansion  is  required  they 
work  admirably,  but  the  complication  they  entail  is  not  desirable. 
For  moderate  power  the  single  cylinder  is  to  be  preferred  as  suffi- 
cient for  all  practical  purposes,  but  for  large  power  we  would  recom- 
mend a  small  high-pressure  cylinder  working  in  connection  with  a 
large  low-pressure  cylinder,  as  the  strain  on  the  machinery  is  not 
so  much  felt,  nor  do  the  parts  require  to  be  of  extra  strength,  as  the 
piston  rods  and  adjuncts  would  require  to  be,  were  the  high-pressure 
steam  from  the  boiler  admitted  on  the  top  of  a  large  piston. 

We  are  indebted  to  Mr.  Marten,  C.E.,  of  Wolverhampton,  for  the 
following  particulars  of  the  pumping  engines  in  use  at  the  water- 
works there. 

The  two  engines  at  Tettenhall  are  single  direct-action  non-con- 
densing engines.  The  cylinders  are  36  inches  in  diameter,  and 
9  feet  6  inches  stroke.  The  plunger  pumps  are  13  inches  in 
diameter,  with  a  lift  of  about  300  feet.  The  steam  is  admitted  to 
the  cylinder  at  a  pressure  of  about  35  lbs.,  and  is  cut  off  at  two- 
thirds  of  the  stroke.  The  boilers  are  cylindrical,  two  in  number, 
26  feet  in  length  and  6  feet  in  diameter,  with  two  tubes  in  each  25^ 
inches  in  diameter,  and  internal  flues;  the  flame  from  each  fireplace 
passes  along  the  tube,  thence  round  to  the  front,  again  by  the  side 
of  the  boiler  next  to  its  tube,  where  the  two  unite  and  pass  along  the 
bottom  into  the  chimney.  The  boilers  are  covered  with  loam  or 
moulding  sand  to  a  depth  of  about  6  inches  from  the  top.  This 
substance,  which  should  be  protected  by  a  roof  from  blowing  away, 
is  found  to  be  a  very  good  non-conductor,  little  heat  radiating 
through  it  to  the  upper  surface;  it  has  also  this  advantage  over 
nearly  all  other  materials  employed  for  the  same  purpose,  that  no 
condensation  can  take  place  in  it  within  2  or  3  inches  of  the  boiler 
plates,  since  for  that  distance  it  forms  a  sand  bath  as  hot  as  the 
steam,  which,  in  the  event  of  a  leakage,  blows  through  it  dry,  and 
consequently  corrosive  action  on  the  plates  is  prevented.  When 
escape  and  condensation  of  steam  takes  place,  it  is  detected  by  a 
moist  patch  on  the  surface  of  the  sand.     With  a  material  of  this 


STATIONARY  ENGINES. 


205 


description,  any  portion  of  the  top  of  the  boiler  can  be  uncovered 
with  a  shovel,  and 
examined  at  once. 
For  the  purpose  of 
experiment,  steam 
blows  at  two  places 
in  the_  boilers  at  Tet- 
tenhall  were  suffered 
to  remain  unrepaired 
for  a  couple  of  years, 
in  order  to  test  the 
value  of  this  covering, 
and  the  result  was 
an  entire  absence  of 
corrosive  action  on 
the  plates.  In  the 
opinion  of  Mr.Marten 
loam  sand  is  much 
preferable  for  this 
purpose  to  any  other 
material,  provided 
that  it  is  protected  by 
a  roof  or  covering.  It 
is  much  cheaper  than 
felt,  brick,  or  sheet 
iron  casing  with  air 
space ;  and  much 
superior  to  furnace 
ashes,  cinders,  or 
riddlings,  which  are 
often  placed  over 
boilers,  as  these  sub- 
stances frequently 
contain  acids  and 
other  chemical  im- 
purities, which  on  be- 
ing brought  in  con- 
tact with  waste  steam 
act   very    injuriously 

on  wrought  iron.  '^'S-  128. — ^Tettenhall  Pumping  Engines.     Elevations  and  Plan. 


MODERN   STEAM   PRACTICE. 


Fig.  129. — Tettenhall  Pumping  Engines.     Side  Elevation. 


STATIONARY   ENGINES. 


207 


1'  ig.  13a — Tettenhall  Pumping  Engines.     Transverse  Section. 


208 


MODERN   STEAM   PRACTICE. 


The  steam,  equilibrium,  and  exhaust  valves  are  of  gun  metal,  and 
on  the  double-beat  construction.     Their  areas  are  as  follows: — 


Steam  valve, 5°  ^q. 

Equilibrium  valve, 50      , 

Exhaust  valve, 78      , 


=  -jj^th  area  of  cylinder. 


The  piston  rod  and  pump  rod  are  connected  with  a  crosshead 
working  on  V-slides  attached  to  the  supporting  columns.  The  plug 
rod  and  the  valve  motion  are  worked  from  a  slight  wrought -iron 
beam  under  the  cylinder  floor,  connected  at  one  end  to  the  cross- 
head,  and  at  the  other  slung  to 
parallel  links.  The  feed  pump  is 
also  attached  to  this  beam,  the 
water  for  the  feed  being  passed 
through  a  heater  situated  in  the 
corner  of  the  engine  house,  and 
formed  by  an  enlargement  of  the 
waste-steam  pipe.  This  heater  is 
I  foot  6  inches  in  diameter;  the 
feed  pipe  is  conducted  along  its 
centre  for  some  distance,  and  oc- 
cupies about  two -thirds  of  its 
area.  The  engine  is  regulated  by 
a  water  cataract,  governed  by  a 
small  ratchet  wheel  and  screw. 
The  number  of  strokes  per  min- 
ute varies  from  three  or  four  to 
ten  or  eleven,  the  average  speed 
of  piston  being  130  to  140  feet 
per  minute;  the  quantity  of  water 
delivered  per  stroke  is  56  gallons. 
The  pumps  are  of  the  plunger 
type,  and  have  the  valves  placed 
at  the  top  of  the  barrel ;  by  this 
means  no  air  can  collect  at  the 
top  of  the  pump,  as  in  ordinary 
plunger  pumps  for  colliery  pur- 
poses. The  area  of  each  plunger 
is  132  square  inches,  and  the 
pressure  on  its  bottom  is  130  lbs.  per  square  inch — making  a  total 
dead  load  of  17,160  lbs.,  equal  to  a  pressure  of  16^  lbs.  per  square 


T^mmmmmmmm. 


Fig.  131. — Sectional  Elevation  of  Pump. 

A,  Suction  pipe.     B,  Suction-valve  chest,     c,  Delivery- 
valve  chest.      D,  Plunger.      E,  Stuffing  box 
and  gland.     F,  Stand  pipe. 


STATIONARY   ENGINES. 


209 


Fig.  132. — Plan  of  Pumps. 


inch   on   the   surface   of   the   steam    piston.      These   engines   are 
worked    at   a  fair  duty,    performing    about    27,000,000   lbs.    hfted 

1  foot  high  per  minute,  with  a  consumption  of  i  cwt.  of  the 
small  slack  in  the  neighbourhood;  with  Newcastle  or  Welsh  small 
coal  they  would  perform  a  duty  of  36,000,000  lbs.  The  pump 
valves  are  of  the  ring  de- 
scription, rising  on  a  central 
spindle;  they  are  made  of  cast 
iron  galvanized,  beating  on 
wooden  faces.  Originally  they 
beat  upon  a  mixture  of  lead 
and  tin,  but  this  soon  became 
loose  in  the  seating,  causing 
leakage;  oak  was  then  tried, 
but  the  acid  peculiar  to  this 
wood  corroded  the  cast  iron, 
and  it  had  to  be  discontinued; 
lancewood,  box,  and  beech 
have  also  been  tried,  but  no  wood  answers  so  well  as  holly,  which 
is  now  used  for  this  class  of  valve.  The  area  of  the  suction  valve  is 
325  square  mches,  being  about  two  and  a  half  times  the  area  of  the 
plunger;  and  that  of  the  delivery  valve  is  163  square  inches,  or  about 
one  and  a  third  times  the  area 
of  the  plunger.  The  enlarge- 
ment of  the  suction  valve  to 
this  extent  is  found  to  be  very 
serviceable  where  the  velocity 
of  the  plunger  is  likely  to  be 
great  in  the  ascending  stroke. 
The  water  was  originally  deli- 
vered over  a  stand  pipe  180 
feet  high,  whence  it  flowed  by 
gravitation  to  the  town;  but 
now  a  reservoir  is  substituted, 
and  -the  stand  pipe  dispensed 
with. 

The  engine  at  Goldthorn  Hill  is  a  low-pressure  condensing  beam 
engine.  The  cylinder  is  48  inches  in  diameter,  with  an  8-feet  stroke. 
The  boilers  are  30  feet  long  and  7  feet  in  diameter,  with  two  tubes, 

2  feet  in  diameter  beyond  the  furnace,  and  2  feet  by  2  feet  4  inches 

14 


Fig.  133. — ^Valve  for  Pump. 

A,  Valve.      B,  Guide  bar.      c,  Valve  seat 
D  D,  Wooden  beats. 


2IO 


MODERN   STEAM   PRACTICE. 


at  the  fireplace. 


Fig.  134.— Kngine  at  Goldthorn  Hill  Water 
works.     Elevations  and  Plan. 


The  pressure  of  the  steam  ;s  about  15  lbs.  per 
square  inch. 

To  avoid  the  almost  constant  trou- 
ble caused  by  leakage  at  the  steam 
valves  on  the  boiler  tops,  from  ex- 
pansion and  contraction  of  the  main 
range  of  steam  pipes,  the  main  steam 
pipe  should  have  a  quadrant  curve 
between  the  boilers,  so  as  to  allow  for 
expansion  and  contraction  without  a 
thrust  sufficient  to  break  any  joints. 
This  arrangement  is  useful  and  effi- 
cient when  there  is  one  steam  pipe 
leading  off  from  between  two  boilers; 
when,  however,  the  steam  pipe  leads 
off  from  one  side,  or  where  there  is  a 
range  of  more  than  two  boilers,  it  is 
not  applicable,  and  in  such  cases,  in 
the  absence  of  packed  expansion 
joints,  no  plan  is  so  simple  and  effec- 
tive as  the  wrought -iron  diaphragm 
joint,  consisting  of  a  couple  of  circu- 
lar wrought- iron  plates,  about  two 
and  a  half  times  the  diameter  of  the 
pipe,  dished  out  about  3  inches,  and 
rivetted  together  at  the  outer  rim  and 
to  flanges  on  the  main  range  of  the 
steam  pipe. 

Another  useful,  although  frequently 
overlooked,  point  of  detail  in  connec- 
tion with  the  boilers,  consists  in  lead- 
ing the  hot  and  cold  feed  and  blow- 
off  into  and  out  of  the  boiler  through 
the  same  pipe.  This  arrangement 
avoids  the  numerous  holes  usually  cut 
in  boilers  for  these  purposes,  and  any 
impurity  which  may  enter  the  boiler 
with  the  hot  and  cold  feed  is  de- 
posited near  to  the  blow-off.  In  the 
present  instance  the  pipe  is  of  wrought 


STATIONARY   ENGINES.  211 

iron,  and  is  rivetted  on  the  under  side  of  the  front  end  of  the  boiler. 
The  arrangement  of  the  valves  is  somewhat  similar  to  those  of  a 
bath,  where  the  hot,  cold,  and  outlet  valves  all  take  off  the  same 
pipe.  It  is  also  important  that  the  feed  should  enter  the  coldest 
portion  of  a  boiler,  which,  from  the  action  of  the  currents  in  those 
with  internal  flues,  is  just  under  the  fire  grate.  When  this  is  not 
attended  to  the  seams  and  rivets  are  apt  to  leak  from  the  sudden 
changes  of  temperature  to  which  they  are  subjected. 

Instead  of  delivering  the  water  over  a  stand  pipe,  as  origi- 
nally in  the  Tettenhall  engine,  the  Goldthorn  Hill  engine  delivers 
through  an  air  vessel  into  two  reservoirs  lying  near  the  engine, 
holding  together  1,500,000  gallons,  and  raised  about  20  feet  above 
the  top  lift.  The  reservoirs  are  arched  over,  and  covered  with 
2  feet  of  soil,  for  the  purpose  of  preventing  vegetation  in  the  water 
and  variation  in  its  temperature.  These  objects  are  well  secured, 
as  the  water  remains  for  months  at  the  same  temperature,  and 
perfectly  free  from  all  vegetable  or  animal  impurities.  The  reser- 
voirs are  kept  from  being  overfilled  by  a  self-acting  check  valve, 
which  shuts  against  any  supply  beyond  a  certain  limit;  and  the 
man  in  charge  of  any  pumping  engine  at  a  distance  at  once  knows 
when  to  stop  work.  The  valve  is  so  arranged  that  when  the  engine 
ceases  to  work  the  supply  from  the  reservoir  to  the  town  is  main- 
tained through  the  flap  valves  placed  underneath  the  self-acting  stop 
valve.  The  object  of  a  stand  pipe  is  that  the  water  may  be  always 
delivered  from  the  engine  over  one  uniform  height,  and  consequently 
of  one  uniform  pressure  on  the  engine,  whatever  varying  circum- 
stances may  affect  the  delivery  after  the  water  has  once  passed  the 
top  of  the  stand  pipe.  For  this  purpose  it  is  useful,  but  it  is  rather 
a  costly  and  unsightly  mode  of  attaining  what  in  practice  is  found 
to  be  an  unnecessary  degree  of  perfection ,  as  at  a  tithe  of  its  cost 
all  the  necessary  safety  can  be  secured  by  pumping  into  an  air 
vessel  with  a  self-acting  valve  on  the  delivery  side,  so  that,  in  case 
of  a  pipe  bursting,  or  any  sudden  diminution  of  pressure  taking 
place,  it  would  be  impossible  for  the  engine  to  "  go  out  of  doors," 
as  it  is  technically  termed,  at  more  than  a  certain  regulated  speed, 
by  the  partial  contraction  of  the  area  of  discharge  through  means 
of  the  check  valve.  Unless,  too,  the  stand  pipes  are  carefully  cased 
in  winter  they  are  in  great  danger  of  being  frozen,  and  very  serious 
consequences  have  arisen  from  this  cause.  The  great  weight  of  the 
column  of  water  requiring  to  be  set  in  motion  from  a  dead  stand  at 


212 


MODERN   STEAM   PRACTICE. 


A,  Accumulator  or 
hydraulic  cylinder. 

B,  Loaded  piston. 


c.  Lower  weights. 

D,  Upper  weights. 

E,  Spiral  spring. 


Fis-  13S. — Valve  Regulator. 


each  stroke  of  the  engine  is 
also  an  objection  to  the  use 
of  the  stand  pipe. 

As  a  substitute  for  these 
tall  stand  pipes,  the  follow- 
ing arrangement  has  been 
adopted  in  the  St.  Peters- 
burg water-works,  recently 
carried  out  by  Messrs.  R. 
Laidlaw  &  Son  of  Glasgow. 
A  throttle  valve  or  regulator 
is  placed  so  as  to  be  con- 
trolled by  the  pressure  of 
the  water  in  the  main.  The 
pressure  acts  through  a 
small  accumulator  or  hy- 
draulic cylinder  fitted  with  a 
loaded  piston  and  attached 
to  the  regulator.  This  loaded 
piston,  as  it  moves  with 
the  varying  pressure  in  the 
mains,  acts  on  the  throttle 
valve,  and  thus  regulates 
the  motion  of  the  engines. 
A  further  arrangement  was 
made  whereby  the  steam 
would  be  automatically  and 
instantaneously  shut  off  if 
any  burst  took  place.  Fig. 
135  shows  the  arrangement 
adopted.  The  lower  weights 
are  slightly  less  than  the 
pressure  on  the  water  piston, 
and  thus  the  piston  spindle 
is  kept  in  contact  with  the 
upper  weights ;  the  steam 
valve  being  then  half  open, 
any  increase  of  pressure  thus 
causes  the  upper  weights 
to  be  raised  and  the  spiral 


STATIONARY   ENGINES.  21 3 

spring  is  compressed  and  the  regulating  valve  closed.  If  a  burst 
takes  place  the  lower  weights  drop  and  instantly  close  the  steam 
valve. 

The  successful  working  of  any  pumping  engine  is  dependent  in 
a  great  degree  upon  the  perfection  of  the  pump  valves,  which  must 
be  so  arranged  as  to  deliver  the  water  with  ease  and  rapidity,  and 
without  any  concussion  in  closing.  As  an  illustration  of  the  great 
practical  importance  of  this  question,  it  may  be  mentioned  that  when 
the  Cornish  pumping  engine  was  first  used  for  water-works  pur- 
poses on  a  large  scale,  it  was  on  the  point  of  being  altogether 
abandoned  on  account  of  the  imperfection  of  the  pump  valves. 
The  valves  were  of  large  area,  and  constructed  on  the  old  butterfly 
principle,  so  that,  under  the  heavy  pressure  at  which  they  were 
worked,  the  concussion  caused  in  shutting  was  so  violent  as  to  occa- 
sion serious  alarm  for  the  safety  of  the  machinery  and  foundations. 
The  difficulty  of  constructing  a  valve  which  should  present  a  maxi- 
mum area  of  discharge  with  a  minimum  area  of  surface  exposed  to 
the  concussion  of  the  recoiling  load  at  the  termination  of  each 
stroke  of  the  pun^p  appeared  for  a  time  insurmountable,  but  was, 
however,  happily  got  over  by  the  introduction  of  the  double-beat 
valve. 

This  valve,  as  already  explained,  has  the  upper  area  con- 
tracted, and  by  the  difference  of  the  upper  beat  and  the  inside  of 
the  lower  one  a  surface  is  afforded  for  the  water  to  act  upon  in 
lifting  and  shutting  the  valve.  The  valve  having  two  points  for 
the  water  to  escape  by,  a  very  slight  distance  of  lift  gives  a  large 
area  for  discharge;  and  the  area  upon  which  the  recoiling  column 
descends  being  only  the  difference  between  the  upper  and  lower 
areas,  and  not  the  entire  area  of  discharge  as  in  the  old  butterfly 
valve,  forms  a  surface  insufficient  to  cause  any  concussion.  This 
valve  also  affords,  under  all  circumstances,  a  means  of  regulating 
the  pressure  tending  to  shut  the  valve,  whatever  may  be  the  height 
of  the  column  of  water  or  the  total  pressure  of  the  recoiling  column, 
by  adjusting  the  difference  of  area  of  the  upper  and  lower  beats 
inversely  in  proportion  to  the  height  of  the  column. 

For  the  ordinary  purposes  of  small  lift  pumps  and  colliery  engines 
the  butterfly  valve  is  serviceable,  as  there  are  no  expensive  faces  to 
be  ground  up  or  deranged  by  impurities  or  grit  in  the  water,  and 
it  can  be  readily  repaired  on  the  spot.  For  a  higher  class  of  work 
there  is  no  description  of  valve  answers  better  than  the  double-beat 


214 


MODERN   STEAM    PRACTICE. 


ring  valve,  similar  to  the  one  employed  in  the  engines  at  Tettenhall 
and  Goldthorn  Hill.  Large  valves  of  this  construction,  from  i6  to 
20  inches  in  diameter,  answer  well  made  of  cast  iron  with  wooden 
beats,  smaller  valves,  from  8  to  15  inches  in  diameter,  are  better 
made  of  gun  metal,  working  face  to  face,  some  of  the  latter  descrip- 
tion having  worked  for  more  than  two  years,  under  a  pressure  of 
260  feet  of  head,  without  any  perceptible  wear. 

At  the  Hull  water-works  a  special  description  of  va?ve  has  been 
adopted  in  one  of  the  pumps  with  great  success.     It  consists,  of  3 


Fig.  136.— Gutta-percha  Ball  Valves  on  Metal  Beatings. 
A,  Valve  seats,     b.  Gutta-percha  balls,     c.  Guard  pieces,     d,  Holding-down  bolt  with  stuffing  box 

•  and  gland. 

pyramid  of  circular  seats,  one  above  another,  in  each  of  which  there 
are  a  number  of  small  circular  beats  about  2  inches  in  diameter, 
into  which  a  corresponding  number  of  gutta-percha  balls  drop.  It 
is  22  inches  in  diameter,  ^nd  works  under  a  head  of  160  feet,  in 
connection  with  a  plunger  pump  with  a  direct-action  steam  cylin- 
der.    The  action  of  this  valve,  as  will  be  seen  from  Fig.  136,  is  very 


STATIONARY   ENGINES.  215 

simple.  It  was  substituted  for  the  double-beat  valve  in  use,  and 
immediately  upon  starting  it  lightened  the  burden  of  the  engines 
about  168  lbs.,  and  has  since  given  great  satisfaction.  This  valve 
possesses  other  advantages.  In  the  first  place  it  is  much  safer  than 
any  other  form  of  valve,  as  will  be  easily  seen.  Supposing  a  piece 
of  wood  or  other  material  should  pass  through  the  pump,  as  is 
frequently  the  case:  if  the  wood  should  be  caught  on  the  beat  of 
the  ordinary  valve,  it  would  hold  the  whole  valve  open  and  let  the 
engine  "come  out"  with  a  run,  possibly  causing  considerable  damage; 
but  with  the  small  balls  of  this  valve  a  piece  of  wood  so  caught 
could  only  affect  one  out  of  fifty-six  balls — so  small  a  percentage 
of  the  whole  opening  that  it  would  merely  enable  the  man  in  charge 
to  perceive  that  there  was  some  trifle  amiss  by  an  increase  of  leak- 
age. In  the  second  place,  the  balls,  being  nearly  of  the  same 
specific  gravity  as  the  water,  are  floated  open  the  moment  the  cur- 
rent turns  in  their  favour;  whereas  in  all  other  valves,  in  addition 
to  the  column  of  water  to  be  lifted,  there  is  also  the  weight  of  the 
heavy  metal  valve  to  be  opened  and  held  suspended  during  each 
stroke.  With  large  valves  this  point  becomes  one  of  great  import- 
ance, as  they  often  weigh  5  to  6  cwts.  each.  Again,  in  this  valve, 
whilst  the  area  of  discharge  may  be  made  fully  equal  to  that  of  the 
plunger,  the  area  exposed  to  concussive  action  in  closing  is  reduced 
to  the  smallest  possible  limits,  being  practically  the  impinging  force 
upon  one  ball,  the  last  one  that  shuts,  or  -gVth  part  of  the  total  area 
of  beating  surface;  this  is  owing  to  the  fact  that  the  balls  do  not 
all  rise  to  the  same  height  above  their  seats,  and  consequently,  as 
the  force  of  the  current  acts  upon  each  ball  separately,  on  the 
cessation  of  motion  each  shuts  in  accordance  with  the  height  it  has 
to  fall,  and  a  communication  exists  between  the  water  on  the  upper 
and  under  side  of  the  valve  until  the  absolute  closing  of  the  last 
ball.  The  result  is,  that  although  the  difference  in  time  between 
the  falling  of  the  various  balls  must  be  exceedingly  minute,  it  is 
such  as  practically  to  prevent  all  concussion.  Lastly,  the  valves 
constructed  on  this  plan  are  very  easily  repaired.  It  is  only  neces- 
sary to  keep  a  few  spare  balls  ready,  to  be  inserted  in  the  place  of 
any  that  may  become  damaged;  and  the  old  ones,  melted  and 
recast  in  a  mould  kept  for  that  purpose,  are  again  as  good  as  new. 

Where  it  is  proposed  to  work  with  a  high  pressure  of  steam,  cut 
off  so  as  to  allow  of  a  considerable  expansion,  the  beam  engine  is 
to  be  preferred  to  the  direct-action  engine;  the  latter,  as  a  rule, 


2l6  MODERN    STEAM    PRACTICE. 

when  working  under  a  high  initial  pressure,  is  apt  to  start  off  at  a 
speed  which  jars  and  strains  the  whole  of  the  machinery.  Besides, 
the  speed  attained  by  the  piston  as  driven  indoors  at  the  beginning 
of  the  stroke  is  many  times  greater  than  the  average  velocity  per 
minute,  and  therefore,  unless  all  the  parts  are  made  proportionally, 
the  bearings  very  quickly  wear  out,  and  the  machinery  is  loose  at 
every  joint.  In  a  beam  engine,  on  the  other  hand,  a  very  large 
proportion  of  the  initial  force  is  absorbed  in  overcoming  the  inertia 
of  the  heavy  beam,  which  thus  serves  as  a  reservoir  of  surplus  force 
in  the  earlier  part  of  the  stroke,  giving  it  out  during  the  later  part, 
with  the  result  that  a  comparatively  steady  velocity  is  maintained 
throughout  the  stroke,  much  to  the  advantage  of  the  whole  ma- 
chinery; indeed,  it  is  only  with  this  adjunct  that  expansion  can  be 
safely  carried  to  a  very  high  degree.  The  beam,  in  fact,  acts  like 
a  fly  wheel,  storing  force  as  required,  and  is  attended  with  precisely 
the  same  beneficial  results. 

For  pumping  a  large  quantity  of  water  through  an  unusually 
great  length  of  main  pipe,  under  a  heavy  pressure,  a  description  of 
engine  may  be  preferred,  consisting  of  a  pair  of  high -pressure 
expansive  double-acting  beam  engines,  coupled  together  at  right 
angles  to  the  fly-wheel  shaft.  The  pumps  in  this  engine  should  be 
of  the  combined  bucket  and  plunger  type.  Each  pump  should  have 
an  air  vessel  and  back-flap  valve,  with  a  blow-off  valve  loaded  to  a 
certain  weight,  so  that  in  the  event  of  any  recoil  in  so  great  a  length 
of  main  the  pumps  would  not  burst.  Along  the  main  pipe,  at  each 
50  feet  of  elevation  above  the  pumps,  a  back-flap  valve  is  required, 
so  that  in  case  of  any  pipe  bursting  the  whole  main  would  not  be 
run  dry.  The  leading  point  to  be  kept  in  view  in  the  design  and 
construction  of  engines  for  such  purposes  is  the  maintenance  of  a 
constantly  uniform  flow  of  water  through  the  main  pipe  from  the 
pumps.  This  is  provided  for  by  the  compound  double-acting 
pumps  and  large  air-vessel  accommodation,  together  with  the 
coupling  of  the  engines  at  right  angles.  Many  engineers  prefer  a 
double-cylinder  engine  for  conducting  expansive  operations;  but 
although  in  some  cases  such  an  engine  is  advantageous,  as  for 
driving  machinery  where  great  regularity  of  motion  is  a  desideratum, 
yet  for  large  pumping  engines  the  single  cylinder  is  preferable,  as 
double-cylinder  engines  are  much  more  complicated,  and  all  useful 
degrees  of  expansion  can  be  obtained  sufficiently  with  a  single 
cylinder. 


STATIONARY   ENGINES. 


217 


The  next  example  gives  the  plan  of  the  water-works  as  adopted  at 
Berwick-on-Tweed.  The  works  comprise  two  tanks  for  storing  spring 
water,  one  with  the  top  water  at  a  level  of  16  feet  above  ordinance 
and  the  other  12  feet  higher.  The  upper  tank,  which  occupies  the  site 
of  an  old  quarry,  is  80  X  50  feet  and  7  feet  deep,  and  has  three  walls 
built  of  dry  rubble  stones,  to  admit  the  water  from  the  springs 


Fig.  137. — General  Arrangement  of  Tanks,  Engine  and  Boiler  Houses,  Berwick-on-Tweed 
Water-works. 


rising  behind  the  walls;  the  wall  next  the  river  is  built  of  water- 
tight masonry  in  cement,  with  a  puddle  wall  at  the  back  of  it.  The 
lower  tank,  which  is  70  X  20  feet  and  7  feet  deep,  has  solid  walls 
like  the  large  one,  and  receives  the  water  from  several  springs,  which 
rise  at  a  lower  level  than  those  stored  in  the  upper  tank.  An  engine 
and  pump  and  boiler,  with  engine  and  boiler  house,  complete  the 
works  at  the  collecting  ground;  and  a  9-inch  rising  main  conducts 


2l8 


MODERN   STEAM   PRACTICE. 


the  water  to  a  high-level  reservoir,  placed  at  a  level  of  about  200  feet 
above  ordinance.  The  springs,  of  which  there  are  several,  are  esti- 
mated to  yield  230,000  gallons  in  the  twenty-four  hours,  and  the 
engine  working  ten  hours  per  day  is  calculated  to  raise  61  cubic  feet 
per  minute.  The  height  being  178  feet,  and  the  length  of  track 
8145  feet,  with  a  diameter  for  the  rising  main  of  9  inches,  the  head 

allowed  for  friction  was  24  feet,  found  by  the  formula  ^=-^-75, 

which  makes  a  total  height  of  202  feet.  To  calculate  the  horse- 
power required  to  raise  the  water  to  the  high  reservoir:  By  the 

ordinary  method         \^'^t^   ^     we  have  a  result  of  24,  and  adding 
■>  33000 

a  fourth  more  for  loss  =  30  horse-power  for  the  engine.     It  is  worthy 

of  remark  that  the  pressure  gauge  on  the  air  vessel  registers  an 

increase  of  10  lbs.,  which  is  equivalent  to  24  feet  of  head  while 


Fig.  138. — Engine  and  Pump. 

working,  and  when  standing  the  pressure  is  reduced  to  that  due  to 
the  statical  pressure,  namely,  178  feet. 

The  engine,  which  is  non-condensing,  and  is  placed  vertically,  is 


STATIONARY   ENGINES. 


219 


Fig.  139. — Pump  Bucket. 


calculated  to  work  with  a  pressure  in  the  boiler  of  40  lbs.  per  square 
inch.     The  piston  is  17  inches  in  diameter,  the  stroke  being  3  feet, 
and  the  number  of  revolutions  of  the  crank  about  thirty-five.     The 
pump  is  double-acting,  consisting  of  bucket  and  plunger;  the  dia- 
meter of  the  barrel  is  18^  inches,  that  of  the  plunger  13^  inches, 
with  a  stroke  of  3  feet     The  bucket  packing  consists  of  rings  of 
gutta  percha  about  i  inch  square  in 
section,  let   into  grooves  cut  in  the 
bucket ;  two  holes,  }4  inch  in  diame- 
ter, are  bored  in  the  top,  communicat- 
ing with  the  grooves,  the  water  pres- 
sure being    always   constant   presses 
out  the  rings  of  gutta  percha,  mak- 
ing them  perfectly  water-tight.     The 
valves  are  of  the  ordinary  flap  kind ; 
a   large   air  vessel    is   fitted   to   the 
pump,   3  feet  6  inches   in  diameter 
and  14  feet  6  inches  high.     The  mo- 
tion for  driving  the  pump  consists  of 
a  pinion  on  the  engine  shaft  and  spur  wheel  on  the  pump  shaft, 
the  gearing  being  in  the  proportion  of  3  to  i.     The  fly  wheel  on 
the  engine  shaft  is  11  feet  in  diameter,  and  weighs  5  tons  12  cwts.; 
a  balance  is  placed  on  the  spur  wheel  to  counterpoise  the  weight  of 
the  pump  ram.     The  boilers  are  26  feet  long  and  6  feet  6  inches  in 
diameter,  with  a  single  flue  3  feet  3  inches  in  diameter ;  the  fire 
grate  is  arranged  underneath,  with  return  side  flues;  thickness  of 
plates  in  body  of  boiler,   ^  inch;  of  end  plates,  }i   inch.     The 
chimney  stalk  is  84  feet  high,  7  feet  6  inches  square  at  the  level  of 
the  ground,  and  3  feet  6  inches  square  at  the  coping.     The  boiler 
is  fed  with  a  small  plunger  pump,  worked  off"  the  end  of  the  piston 
crosshead,  the  water  being   previously  heated  in  a  tank  by  the 
exhaust  steam.      The  engine  and  pump  cost  ^^950.     The  rising 
main,  9  inches  in  diameter,  has  turned  and  bored  joints  except 
where  lead  and  yarn  ones  were  required  for  sharp  bends;  and  also 
four  air  and  four  scouring  plug  valves  with  a  clack  valve  immediately 
above  the  air  vessel  and  another  half-way  up  the  track.     A  branch 
pipe  leads  into  the  lower  service  cistern,  fitted  with  a  self-acting 
ball  valve,  6  inches  in  diameter.     The  pipes  cost  when  laid  about 
I2S.  per  lineal  yard.     The  actual  work  done  by  the  engine  can  be 
determined  by  means  of  a  cast-iron  measuring  box  placed  at  the 


220  MODERN   STEAM   PRACTICE. 

upper  end   of  the  pipe,  with  a  trough  having  a  flap  valve  in  the 
bottom  for  passing  the  water  direct  into  the  cistern  if  required. 

By  means  of  an  indicator  diagram  we  can  calculate  the  amount 
of  work  required  to  raise  the  water  from  the  lower  tank  to  the  high 
reservoir  as  follows: — The  measuring  box  is  6  feet  X  3  feet  3  inches  x 
3  feet  i}i  inch,  and  has  a  capacity  of  60*64  cubic  feet.  The  aver- 
ages of  four  experiments  made  by  the  engineer  for  the  works  gave 
58*25  seconds  as  the  time  required  to  fill  the  box,  which  represents 
a  discharge  of  62*5  cubic  feet  per  minute.  The  area  of  the  plunger 
of  the  pump  being  "9398  foot,  and  the  double  stroke  6  feet — the 
engine  making  thirty-five  revolutions  per  minute,  which  represents 
11*66  of  the  plunger — gives  a  theoretical  discharge  of  65*73  cubic 
feet  per  minute,  and  shows  a  ratio  between  the  theoretical  and 
actual  of  100  :  95,  or  a  loss  of  5  per  cent.  This  represents  an  amount 
of  work  =  62*5  cubic  feet,  weighing  3906  lbs.,  raised  202  feet  high, 
which  is  equal  to  an  expenditure  of  23.9  horse -power.  The  indi- 
cator diagram  showed  an  effective  pressure  of  23  lbs.  per  square 
inch,  which  with  thirty-five  strokes  per  minute  at  6  feet,  with  a  piston 
of  224*5  square  inches,  is  =  33  horse-power,  showing  a  loss  for  fric- 
tion, &c.,  of  2y  per  cent. 

CONSUMPTION    AND   COST   WITH   VARIOUS   KINDS    OF   COAL. 


per  ion. 

per  hour. 

per  horse-power 
per  hour. 

per  horse-power 
per  hour. 

Broomhill  Nuts ... 

...at  6/6   .. 

.    burn  37  cwts.   - 

...   =  17-3  lbs.    . 

..    =  ■6o2d. 

Berwick  Hill 

... ,,  9/6  ... 

>>     2  5      >» 

...   =  117    „     . 

..    =   -586^. 

Scremerston 

...  ,.  9/6  .. 

.,     27      „     . 

...    =  12-6    „     . 

..    =   -631^. 

The  above  table  compares  the  consumption  and  cost  of  coal  with 
the  actual  quantity  of  water  delivered,  which  is  equal  to  an  expen- 
diture of  24  horse-power.  If  we  compare  the  expense  of  working 
this  engine  with  larger  ones  in  use  at  some  of  the  English  water 
works,  and  use  the  same  standard — namely,  the  cost  of  raising  1000 
gallons  100  feet,  which  is  equal  to  1,000,000  foot-pounds,  we  find — 

The  Trent  Water- works  Company  at  Nottingham cost  'zS'jd. 

Boulton  &  Watts,  29  horse-power,  1809,  condensing, ,,    '543^. 

>>  M       3°/^         »»  )»  j>  »»    '35^^- 

„       76  „  1828,  „  ,    -333^. 

Berwick  Pumping  Engine,  1871  (high-pressure), ,,     "34a/. 


STATIONARY   ENGINES.  221 


STAND   PIPES,   ETC. 


Stand  pipes  were  originally  introduced  to  equalize  the  weight  on 
the  engines,  and  give  the  required  pressure  in  the  main  pipes  for 
the  town  supply.  The  arrangement  under  notice  was  erected  at 
Tettenhall,  and  consisted  of  two  pipes,  one  of  them  open  at  the  top, 
inclosed  in  a  tower  of  brickwork,  as  shown  in  Fig.  140. 

We  are  indebted  to  Mr.  Marten,  C.E.,  for  the  following  descrip- 
tion of  its  action: — The  engine  having  only  steam  on  the  under 
side  of  the  piston  lifted  the  pump  rods,  and  their  own  weight 
was  just  sufficient  to  bring  them  down  along  with  the  plunger  of 
the  pump  if  the  stand  pipe  was  only  full  to  the  junction  at  the  top, 
but  it  was  not  enough  to  let  them  force  the  water  to  the  top  of  the 
tower.  When  the  town  required  all  the  water  the  engine  pumped 
regularly,  being  worked  by  a  cataract  to  give  the  requisite  number 
of  strokes  per  minute;  but  if  the  town  did  not  take  the  water  the 
engine  stood,  because  the  rods  were  not  heavy  enough  to  make  the 
down  stroke.  Whenever  the  town  drew  off  some  water  the  engines 
started  again.  The  state  of  the  water  in  the  stand  pipe  was  shown 
in  the  engine  house  by  a  mercury  gauge,  and  the  engines  were 
regulated  to  keep  the  stand  pipe  full  up  to  the  junction.  There 
were  no  escape  valves,  because  they  were  not  needed;  if  by  any 
chance  the  sudden  shutting  of  the  large  mains  in  the  town,  or  air 
returning  up  the  main,  threw  the  water  over  the  top  of  the  stand 
pipe,  it  filled  the  cap  of  the  tower  and  ran  out  at  small  holes,  falling 
like  rain,  but  this  very  seldom  happened.  When  there  is  much 
danger  of  overflow  near  a  town  an  overflow  pipe  is  fitted,  which 
allows  the  water  to  flow  into  the  reservoirs  from  which  it  is  pumped. 
At  Tettenhall  there  was  no  provision  made  for  breaking  the  fall  of 
the  water  in  the  descending  leg  of  the  stand  pipe.  This  want  caused 
much  air  to  be  carried  into  the  mains,  so  that  the  water  when  first 
drawn  was  often  as  white  as  milk  with  the  minute  bubbles  of  air, 
but  it  cleared  in  a  very  short  time.  The  chief  use  of  the  stand  pipe 
was  to  render  undue  pressure  on  the  mains  impossible,  as  there  was 
at  first  no  reservoir.  When  a  reservoir  exists,  however,  always  open 
to  the  pumping  main,  it  serves  the  purpose  of  a  stand  pipe,  and 
prevents  any  undue  pressure. 

In  some  cases,  as  the  South  Staffordshire  water-works  at  Bromhills 
(Fig.  141),  the  stand  pipe  is  placed  on  a  hill  on  the  line  of  the  main, 
about  half-way  between  the  engine  at  Lichfield  and  the  main  reser- 


222  MODERN   STEAM   PRACTICE. 

voir  at  Walsall,  and  it  there  acts  both  as  an  air  pipe  and  a  safety 


'^^ 


> 


^^ \       _._ 

Fig.  140. — Stand  Pipe  and  Tower. 
A,  Pipe  from  the  pumps,    b,  Pipe  to  the  town,    c.  Cap.    d,  Ladder,    e,  Windows, 


STATIONARY   ENGINES.  22^ 

pipe.  At  Bromhills  there  is  only  one  stand  pipe,  open  at  the  top, 
and  placed  in  the  centre  of  a  brick  tower;  if  it  overflows  the  water 
falls  down  the  tower,  and  flows  into  a  canal. 

Mr.  Marten  states  that  he  has  found  a  6-inch  weighted  valve,  on 
a  9-inch  pumping  main,  do  as  well  as  a  stand  pipe,  and  it  prevents 
the  required  pressure  from  being  exceeded.  At  Stourbridge  a  small 
district  near  the  reservoir  needs  higher  pressure  than  the  reservoir 
gives,  and  a  valve  on  the  main  is  weighted  to  give  the  required 


Fig.  141.— Stand  Pipe,  &c. 

pressure,  the  escape  water  passing  into  the  reservoir.  This  valve 
can  be  even  made  self-acting,  as  it  does  not  quite  close,  and  allows 
the  quantity  of  water  to  pass  delivered  by  the  engine  at  its  ordinary 
speed;  and  when  the  engine  delivers  the  quantity  of  two  or  three 
extra  strokes,  the  pressure  rises,  but  never  beyond  the  50-feet  extra 
head  required.  As  the  main  to  the  reservoir  is  also  the  supply  main 
there  is  a  back-flap  valve  on  it  in  the  same  box  as  the  weighted 
valves,  which  opens  whenever  the  engine  stops,  and  lets  the  reser- 
voir water  return.  There  is  also  a  similar  valve  at  the  engine  house, 
about  half  a  mile  from  the  reservoir,  which  enables  the  engine  to 
send  direct  into  the  town  without  a  reservoir  or  open-ended  pipe; 
but  this  plan  is  not  adopted  except  in  cases  of  repair  of  the  main 
or  reservoir. 

Various  valves  are  in  use  for  preventing  the  engine  running  away 
if  a  main  pipe  bursts,  and  they  are  generally  placed  beyond  the  air 
vessel  when  so  fitted.  A  catch,  kept  open  by  the  pressure,  is  some- 
times used;  if  the  pressure  in  the  main  pipe  falls,  the  engines  are 
stopped  by  this  catch  preventing  the  steam  valve  from  opening. 
Mr.  Marten  states  that  when  testing  a  long  main  he  was  surprised 
to  note  the  instantaneous  action  of  the  water;  any  alteration  of  the 
pressure  was  so  instantly  seen  at  the  other  end  that  no  difference 
in  time  could  be  detected.  On  the  South  Staffordshire  main  from 
Lichfield  to  Walsall,  at  every  20  feet  or  so  of  rise  a  back  stop  valve 


224  MODERN    STEAM   PRACTICE. 

is  fitted  to  prevent  the  return  of  the  water  if  the  engine  is  stopped  or 
a  pipe  bursts.  In  the  case  of  the  latter  accident  it  is  of  importance 
to  prevent  much  water  escaping,  as  the  pipe  is  laid  for  some  distance 
along  a  railway  embankment  formed  of  gravel  and  sand,  easily 
washed  away.  During  the  testing  of  the  main  one  pipe  burst  where 
there  had  been  a  chill  in  the  casting,  but  so  little  water  came  out 
as  to  do  but  little  damage  to  the  embankment.  The  engine  stopped 
because  of  the  sudden  drop  of  the  pressure  acting  on  the  catch 
already  referred  to;  and  the  return  of  the  water  was  prevented  by 
the  back  valves,  even  the  water  between  the  burst  and  the  next 
valve  placed  above  being  retained,  as  no  air  could  get  in  except  in 
gulps  at  the  break. 

Many  things  which  were  once  considered  necessary  to  the  safety 
of  water-works  are  now  superseded.  The  constant  system,  or  one 
reservoir  for  the  whole  town,  instead  of  each  customer  having  one 
for  himself,  has  caused  great  change.  Instead  of  the  supply  pipes 
being  led  off  small  pipes  called  "  riders,"  they  are  put  direct  into 
the  main,  and  all  the  ends  of  the  main  are  connected,  so  as  to  give 
greater  circulation  to  the  water.  The  use  of  cisterns  is  discouraged 
as  much  as  possible,  as  they  are  likely  to  deteriorate  the  quality  of 
the  water.  Separate  pipes  to  the  reservoir — one  to  pump  through 
and  the  other  to  supply  through — are  not  used,  but  only  one  pipe 
for  both  purposes. 

It  often  happens  that  the  supply  is  obtained  from  a  spot  between 
the  town  and  the  high  ground  where  the  reservoir  can  be  made : 
one  pipe  from  the  reservoir  is  then  found  sufficient,  and  the  engine 
pumps  into  it.  If  the  town,  as  in  the  middle  of  the  day,  requires 
all  the  water,  it  is  sent  direct  into  it;  when  the  demand  falls  off,  it 
is  partly  delivered  into  the  reservoir;  if  there  is  an  extraordinary 
demand,  both  the  reservoir  and  engines  supply  the  town.  By  this 
arrangement  one  main  answers,  and  it  may  be  much  smaller  than 
if  two  were  used,  one  to  the  reservoir  and  another  from  it  to  the 
town.  Much  of  the  water,  also,  is  pumped  at  a  less  pressure  than 
would  be  needed  to  pump  it  entirely  into  the  reservoir. 

Stand  pipes  may  be  considered  as  among  the  precautionary  con- 
trivances once  deemed  requisite  for  supplying  water  to  a  town ;  but 
the  supply  can  be  obtained  direct  from  an  engine  as  easily  and 
safely  by  properly  loaded  valves,  although  it  is  found  a  more  expen- 
sive plan.  The  engines  do  wretched  duty,  as  the  calls  upon  them 
are  so  irregular.     An  engine  always  does  best  when  working  regu- 


STATIONARY   ENGINES. 


225 


larly  at  full  speed,  and  therefore  a  reservoir  to  receive  the  pumped 
water  should  be  provided  if  possible. 

When  pumping  under  a  heavy  pressure  it  is  usual  to  have  an  air 
vessel  to  each  engine  on  the  delivery  pipe  beyond  the  pumps; 
and  sometimes  a  larger  one  is  placed  on  the  main  pipe  into  which 
the  others  deliver.  Of  course  care  must  be  taken  that  each  air 
vessel  has  its  full  complement  of  air;  sufficient  is  usually  drawn  in 


Fig.  142. — ^Air  Vessels. 
A  A,  Pumps.     B  B,  Air  vessels,     c  c.  Sluice  valves,     d.  Main  air  vessel.     K,  Main  pipe  to  the  town. 

by  the  pump,  and  a  very  small  hole  or  tap  is  sometimes  inserted  to 
supply  it 

When  more  than  one  pump  is  arranged  for  pumping  into  an  air 
vessel,  stop  valves  must  be  fitted  on  the  delivery  pipe,  to  prevent 
the  return  of  the  water  when  either  or  both  pumps  are  not  at 
work.  The  air  vessel  is  of  great  importance,  as  it  equalizes  the  flow 
of  the  water  through  the  main, 
and  less  weight  is  required  on 
the  top  of  the  plunger  for  the 
down  stroke.  The  capacity  of 
the  air  vessel  should  be  about 
ten  times  the  volume  of  water 
delivered  by  each  stroke  of  the 
pump. 

A  relief  valve  should  be  placed 
on  the  delivery  pipe  to  prevent 
undue  pressure;  it  is  fitted  with 
a  lever  and  weight.  In  some 
examples  a  solid  plunger  is 
adopted,  having  a  piston  and 
rod  at  the  top,  the  piston  work- 
ing loosely  in  a  cylinder  connected  to  the  main  by  a  small  pipe. 
The  plunger  A  rises  when  the  pressure  increases,  being  larger  at  A 
than  at  C,  and  allows  the  water  to  flow  through  the  slots  into  the 

IS 


Fig.  143.— Relief  Valve. 

A,  Solid  plunger.  B,  Piston,  c,  Slotted  pipe  leading 
to  reservoir.  D,  Pipe  connecting  the  cylinder  with 
the  main,     e,  Waste  pipe  leading  to  the  reservoir. 


226 


MODERN    STEAM   PRACTICE. 


reservoir  from  which  it  is  pumped,  thereby  reHeving  the  pressure. 
The  plunger  falls  again  by  gravitation,  and 
the  piston  B,  acting  like  a  cataract,  prevents 
the  action  taking  place  too  suddenly. 

The  pressure  valve  is  placed  beyond  the 
air  vessel  on  the  main  pipe;  its  sole  use  is 
to  prevent  the  plunger  of  the  engine  de- 
scending too  rapidly  in  the  event  of  one  of 
the  main  pipes  bursting.  The  example  under 
notice  consists  of  a  plunger,  loaded  with  a 
certain  weight  to  suit  the  head  of  water;  on 
the  bottom  of  the  plunger  a  double-beat  valve 
is  secured  by  a  cotter,  the  valve  working  on 
a  seat  bolted  down  by  bolts  passing  through 
it,  and  secured  by  lugs  at  the  bottom  of  the 
bent  pipe  and  nuts  at  the  top  bearing  on 
Fig.  i44.-Pressure  Valve.        ^he  valvc  scat.     At  cach  strokc  of  the  en- 

A,  Plunger.  B, Valve  chest,  c, Guides.  _•  ,i   ■  i  •       i-r,       11  ,^ 

D,  Valve.     E.  Stuffing  box.      g^e  this  valve  IS  lifted,   and  consequently 
F,  Branch  pipe  from  pump.  G,  De-  ^crc  a  pipe  bursting  tlic  engine  has  still  the 

livery  branch,     w,  Weight. 

same  duty  to  perform.  As  has  been  stated, 
a  modification  of  these  valves  has  been  successfully  used  instead  of 
stand  pipes. 


PUMPING   ENGINES   FOR   DRAINAGE  WORKS   AND 
GENERAL   PURPOSES. 

THE   LONDON   DRAINAGE   SYSTEM. 

The  Abbey  Mills  Pumping  Station  is  the  largest  establishment 
of  the  kind  on  the  Main  Drainage  Works,  and  provides,  by  means 
of  eight  engines,  an  aggregate  horse-power  of  1 140,  capable  of  lift- 
ing 15,000  cubic  feet  of  sewage  and  rainfall  a  height  of  36  feet  per 
minute.  Each  of  the  eight  engines  is  furnished  with  two  boilers; 
and  they  are  contained  in  a  cruciform  building,  arranged  in  pairs, 
each  arm  of  the  cross  containing  two  engines.  The  engines,  as 
in  all  the  other  pumping  establishments  on  these  works,  are  expan- 
sive, condensing,  rotative  beam  engines,  but  are  somewhat  more 
powerful  than  those  used  elsewhere,  the  cylinders  being  4  feet 
6  inches  in  diameter,  with  a  stroke  of  9  feet.  The  pumps  differ  also 
in   being  double-acting,  a  circumstance  which  admits  of  the  air 


STATIONARY   ENGINES.  22/ 

pump,  &c.,  being  worked  from  the  main  beam,  instead  of  from  a 


Fig.  145.— Abbey  Mills  Pumping  Engines.     One-half  Elevation. 


228  MODERN   STEAM   PRACTICE. 

distinct  beam,  as  at  the  other  stations.  Each  engine  works  two 
pumps,  having  a  diameter  of  3  feet  10^  inches,  and  a  length  of 
stroke  of  4}4  feet.  The  boilers  are  each  8  feet  in  diameter  and 
30  feet  long,  with  double  furnaces. 

The  engine  building  is  divided  in  height  into  three  compartments, 
the  lower  one  being  the  pump  well  into  which  the  sewage  is  con- 
veyed from  the  Low  Level  Sewer,  the  second  forming  a  reservoir 
for  condensing  water,  and  the  upper  one  containing  the  eight  engines 
and  platform  overhead.  The  lower  part  of  this  building  lies  about 
3  feet  above  the  bottom  of  a  thick  stratum  of  clay,  overlying  a  consid- 
erable thickness  of  sand  with  water,  through  which  the  foundations 
are  carried  by  piling  to  a  bed  of  firm  gravel  below.  The  boiler  houses 
and  other  portions  of  the  work  are  founded  upon  the  clay  stratum 
overlying  the  sand.  As  the  deep  foundations  are  situated  in  close 
proximity  to  the  Northern  Outfall  Sewer,  which  is  contained  in  an 
embankment  above  the  general  level  of  the  ground,  great  caution  was 
requisite  to  prevent  any  settlement  in  that  sewer.  The  boiler  house 
and  coal  stores  are  built  between  the  outfall  sewer  and  the  engine 
house,  so  as  to  keep  the  deep  excavations  as  far  distant  from  the 
sewer  as  practicable.  The  coal  stores  are  built  with  their  floors  level 
with  the  stoke  holes  in  the  boiler  house,  and.  tramways  are  laid  from 
one  to  the  other;  this  floor  is  only  a  trifle  below  the  surface  of  the 
ground,  which  is  6  feet  below  high  water.  One  side  of  the  coal 
stores  forms  the  front  side  of  the  boiler  house.  Tramways  are  laid 
from  the  top  of  the  coal  stores  to  the  Abbey  Mill  River,  adjacent 
to  the  works,  where  a  wharf  wall  is  built  for  landing  coal  and  other 
materials. 

The  sewage  from  the  Low  Level  Sewer,  before  entering  the  pump 
wells,  passes  through  open  iron  cages,  the  bars  of  which  intercept 
any  substances  likely  to  interfere  with  the  proper  action  of  the 
pump  valves;  and  these  cages  when  requisite  are  lifted  above  ground 
by  proper  gearing,  and  the  intercepted  matter  is  discharged  into 
trucks.  The  sewage  then  passes  into  the  wells,  and  is  lifted  by  the 
pumps  through  the  hanging  valves  into  a  circular  culvert  of  cast 
iron,  and  then  forced  into  any  of  the  three  culverts  forming  the 
Northern  Outfall  Sewers. 

It  is  fortunate  that  these  works  were  not  projected  in  the  year 
1306,  when  coal  was  first  introduced  into  London,  and  was  regarded 
as  so  great  a  nuisance  that  the  resident  nobility  obtained  a  royal 
proclamation  prohibiting  its  use  under  severe  penalties;   for  this 


STATIONARY   ENGINES.  229 

pumping  station  alone  consumes  about  9700  tons  of  coal  per  annum. 
The  expense  of  pumping,  however,  cannot  be  regarded  as  a  wholly- 
additional  item  in  the  cost  of  drainage  under  the  new  system;  for 
the  removal  of  deposit  from  the  tide-locked  and  stagnant  sewers  in 
London  formerly  cost  about  ;i^30,000  per  annum,  and  the  constant 
flow  kept  up  in  the  sewers  by  means  of  pumping  must  necessarily 
keep  them  freer  of  deposit,  and  so  reduce  the  outlay  for  cleaning 
them. 

The  Deptford  Pumping  Station  is  situated  by  the  side  of  Dept- 
ford  Creek,  and  close  to  the  Greenwich  Railway  Station.  The 
sewage  is  here  lifted  from  the  Low  Level  Sewer,  a  height  of  18  feet, 
into  the  Outfall  Sewer.  An  iron  wharf  wall  and  barge  bed,  500  feet 
long,  has  been  constructed  at  the  side  of  the  creek,  and  is  provided 
with  a  crane  and  tramways  for  landing  coal  or  other  materials. 
There  are  four  expansive,  condensing,  rotative  beam  engines,  each 
125  horse-power,  and  capable  together  of  lifting  10,000  cubic  feet 
of  sewage  a  height  of  18  feet  per  minute.  These  engines  are  sup- 
plied by  ten  Cornish  single -flued  boilers,  each  30  feet  long  and 
6  feet  in  diameter.  The  cylinders  are  48  inches  in  diameter,  with 
a  length  of  stroke  of  9  feet  The  pumps,  two  of  which  are  worked 
by  an  engine  direct  from  the  beam,  are  single-acting  plunger  pumps, 
the  diameter  of  the  plungers  being  7  feet,  and  the  length  of  stroke 
4j^  feet:  one  pump  is  worked  from  the  beam  midway  between  the 
steam  cylinder  and  the  centre  pillars,  and  the  other  midway  between 
the  centre  pillars  and  the  fly  wheel.  The  air,  feed,  and  cold-water 
pumps  are  worked  by  a  separate  beam  attached  to  the  cylinder  end 
of  the  main  beam.  The  pump  valves  are  of  the  leather-faced  hanging 
kind,  and  the  sewage  is  discharged  through  them  into  a  wrought- 
iron  culvert  placed  on  the  level  of  the  Outfall  Sewer,  with  which  it 
is  connected  by  a  brick  culvert,  which  receives  also  the  sewage  from 
the  High  Level  Sewer,  previously  brought  by  gravitation  under  the 
creek  through  four  cast-iron  pipes  3  feet  6  inches  in  diameter. 
Both  streams  enter  the  Outfall  Sewer,  and  are  conveyed  to  Cross- 
ness, where  they  are  again  lifted.  The  chimney  shaft  at  this  station 
is  y}4  feet  in  diameter  at  the  base  and  6  feet  at  the  top;  its  height 
is  150  feet,  and  the  furnaces  draw  from  the  sewers  and  the  engine- 
well  to  assist  in  their  ventilation.  The  accommodation  for  coal  is 
ample,  the  sheds  covering  an  area  of  18,000  feet.  Gratings  are 
used  for  intercepting  the  larger  substances  brought  down  by  the 
sewers,  in  the  same  manner  as  at  the  other  pumping  stations. 


230  MODERN   STEAM   PRACTICE. 

The  Crossness  Reservoir  and  Pumping  Station. — The  sewage  on 
the  south  side  of  the  Thames  is  discharged  into  the  river  at  the 
time  of  high  water  only;  but  the  sewer  is  at  such  a  level  that  it  can 
discharge  its  full  volume  by  gravitation  about  the  time  of  low  water. 
Its  outlet  is  ordinarily  closed  by  a  pen  stock  placed  across  its 
mouth,  and  its  contents  are  raised  by  pumping  into  the  reservoir, 
which  is  built  at  the  same  level  as  that  on  the  north  side,  and,  like 
it,  retains  the  sewage,  except  during  the  two  hours  of  discharge 
after  high  water.  The  sewage  is  thus  diverted  from  its  direct  course 
to  the  river  into  a  side  channel  leading  to  the  pump  well,  Avhich 
forms  the  lower  part  of  the  engine  building;  from  this  well  it  is 
lifted  by  four  condensing  rotative  beam  engines,  each  125  horse- 
power, working  direct  from  the  beam  two  compound  pumps,  each 
with  four  plungers.  The  cylinders  are  4  feet  in  diameter,  with  a 
length  of  stroke  of  9  feet;  they  are  situate  at  the  end  of  the  main 
beam,  which  is  40  feet  in  length,  the  crank  shaft  connecting  rod  being 
attached  to  the  farther  end,  and  the  pump  rods  situated  on  either 
side  of  the  beam  centre.  The  air,  feed,  and  cold-water  pumps  are 
worked  by  a  separate  or  counter  beam,  fixed  at  one  end  to  a  rock- 
ing lever,  and  attached  at  the  other  end  to  the  main  beam.  The 
cylinders  are  supplied  by  twelve  Cornish  boilers,  each  6  feet  in 
diameter  and  30  feet  long,  with  an  internal  furnace  and  flue  3  feet 
in  diameter,  set  so  as  to  have  the  second  heat  carried  with  a  split 
draught  along  the  sides,  and  the  third  heat  under  the  bottom  of  the 
boiler,  into  the  main  flue  leading  to  the  chimney.  The  maximum 
quantity  of  sewage  ordinarily  requiring  to  be  lifted  by  these  engines 
is  about  10,000  cubic  feet  per  minute;  but  during  the  night  that 
quantity  will  be  considerably  reduced,  and,  on  the  other  hand,  it 
will  be  nearly  doubled  on  occasions  of  heavy  rainfall.  The  lift  also 
will  vary  from  10  to  30  feet,  according  to  the  level  of  water  in  the 
sewer  and  in  the  reservoir  into  which  it  is  lifted.  These  variable 
conditions  led  to  some  difficulty  in  the  working,  but  which  has  been 
overcome  by  an  arrangement  of  the  pump  plungers.  The  pumps, 
which  are  single-acting,  are  placed  equidistant  on  each  side  of  the 
beam  centre,  their  cases  being  each  12  feet  in  diameter,  and  fitted 
with  four  plungers  4  feet  6  inches  in  diameter.  These  plungers  are 
placed  in  pairs,  each  pair  being  worked  from  a  crosshead  on  the 
main  beam,  which  is  in  two  flitches  for  this  purpose,  and  either 
pair  of  plungers  can  be  thrown  out  of  gear.  By  this  means  the 
capacity  of  the  pumps  may  be  varied  in  the  proportion  of  one,  two, 


STATIONARY   ENGINES. 


231 


or  three,  as  the  inner  pair,  outer  pair,  or  both  pairs  are  thrown  out 
of  gear.     The   sewage   is  discharged   into  a  wrought-iron  trough, 


Fig.  146. — Pumping  Engines  at  Crossness.     One-half  Side  Elevation. 

through  hinged  leather-faced  valves,  which  are  suspended  from 
wrought-iron  shackles,  and  fitted  with  wrought-iron  back  and  front 
plates.  Each  valve  is  12  inches  by  18.  As  has  been  before  stated, 
substances  which  might  prevent  the  proper  action  of  the  valves  are 


232. 


MODERN    STEAM    PRACTICE. 


Fig.  147. — Pumping  Engines  at  Crossness.     End  Elevation. 

intercepted  before  reaching  the  pumps  by  a  wrought-iron  grating 


STATIONARY   ENGINES. 


233 


placed  in  front  of  the  openings  to  the  pump  well.  Such  substances 
are  lifted  from  the  face  of  the  grating  by  an  endless  chain  with 
buckets  or  scrapers  and  combs  attached,  working  vertically  in  front 
of  and  close  to  the  grating,  the  teeth  of  the  combs  passing  between 
the  bars.  On  the  descent  of  the  chain  the  buckets  are  overturned 
and  discharge  their  contents  into  a  trough,  from  which  they  are 
removed  by  manual  labour. 

The  sewage,  after  being  delivered  from  the  pumps  into  the 
wrought-iron  trough,  is  discharged  through  brick  culverts  into  the 
reservoir,  or,  in  case  of  need,  provision  is  made  for  its  discharge 
through  other  culverts  directly  into  the  river.  After  remaining  iri 
the  reservoir  until  the  time  of  high  water,  it  is  discharged  by  a  lower 


Fig.  148. — Boilers  for  Pumping  Engines  at  Crossness.     End  Elevation, 


set  of  culverts  into  the  river.     There  are  two  tiers  of  eight  openings 
in  each  compartment  of  the  reservoir,  the  upper  eight  for  the  admis- 


234  MODERN    STEAM   PRACTICE. 

sion  of  the  sev/age  from  the  pumps  to  the  reservoir,  and  the  lower 
eight  for  its  discharge  into  the  river.  These  apertures  are  all  opened 
and  closed  by  pen  stocks. 

The  reservoir,  which  is  6%  acres  in  extent,  is  covered  by  brick 
arches,  supported  on  brick  piers,  and  is  furnished  with  weirs  for 
overflows,  and  with  a  flushing  culvert.  The  height,  level,  and 
general  construction  are  similar  to  the  one  at  Barking  Creek.  Over 
the  reservoir  are  built  twenty-one  cottages,  for  the  engineers  and 
other  persons  employed  upon  the  works. 

The  ground  upon  which  these  works  are  constructed  consists  of 
peat,  sand,  or  soft  silty  clay,  and  affords  an  insufficient  foundation 
within  25  feet  of  the  surface.  To  obviate  the  need  of  removing  this 
vast  mass  of  soil,  and  thereby  reduce  the  expense  of  the  foundations, 
trenches  were  cut  down  to  the  solid  earth,  and  the  culverts  on  the 
various  levels  were  built  as  far  as  practicable  in  the  same  trenches, 
one  above  the  other;  the  lowest,  leading  from  the  Outfall  Sewer  to 
the  pump  wells,  support  those  discharging  the  sewage  from  the 
reservoir,  and  these  again  support  those  leading  from  the  pumps 
into  the  reservoir.  On  account  of  the  pump  wells  it  was  necessary 
that  the  walls  of  the  engine  house  should  be  carried  down  to  the 
depth  of  the  gravel,  independently  of  the  nature  of  the  ground;  but 
such  was  not  the  case  with  the  boiler  house.  The  boilers  and  stoke- 
hole floor  are  supported  on  arches  springing  from  walls  built  up 
from  the  gravel,  and  the  space  below  the  floor  is  made  available  as 
a  reservoir  for  condensed  water.  The  water  from  the  hot  and  cold 
wells  of  the  engines  is  conveyed  hither,  one  compartment  being 
used  as  a  chamber  for  cooling  that  from  the  hot  well,  previous  to 
its  being  used  again  for  condensing  water.  With  the  same  object 
of  saving  separate  foundations,  coal  stores  and  workshops  have  been 
erected  partly  on  the  external  walls  of  the  reservoir  and  partly  on 
the  culverts  in  front  of  them;  large  coal  stores  being  also  provided 
in  front  of  the  boiler  house  and  on  a  level  with  the  stoke  holes,  into 
which  the  coals  are  brought  on  tramways.  There  is  also  a  tramway 
for  the  upper-level  coal  sheds,  on  the  level  of  the  tops  of  the  boilers, 
from  whence  the  coals  are  shot  into  the  stoke  holes  below.  Tram- 
ways are  also  laid  from  the  coal  sheds  to  the  river,  where  jetties  are 
built  for  landing  the  coals.  A  wall  has  been  constructed  along  the 
fiver  frontage  of  the  works  for  a  distance  of  about  1200  feet,  by 
which  a  large  portion  of  the  "Saltings"  has  been  reclaimed.  This 
wall  is  of  brick,  carried  upon  brick  arches  resting  on  piers  formed 


STATIONARY   ENGINES.  235 

of  iron  caissons  filled  with  concrete,  which  are  carried  down  to  the 
gravel. 

The  chimney  into  which  the  flues  from  the  boilers  are  conveyed 
is  square  in  plan  externally,  8  feet  3  inches  in  internal  diameter 
throughout,  and  200  feet  high;  it  is  founded  upon  a  wide  bed  of 
concrete  brought  up  from  the  gravel,  which  is  here  26  feet  below 
the  surface.  The  reservoir,  the  several  culverts,  and  the  pump  wells 
are  connected  by  flues  with  the  furnaces  of  the  boilers,  for  the  pur- 
pose of  ventilation,  in  the  same  way  as  at  the  Deptford  and  other 
pumping  stations. 

The  outlet  into  the  river  from  the  Outfall  Sewer  of  these  works 
consists  of  twelve  iron  pipes,  each  4  feet  4  inches  in  diameter,  car- 
ried under  the  "Saltings"  into  a  paved  channel  formed  in  the  bed 
of  the  river.  These  pipes  are  connected  with  the  Outfall  Sewer  by 
culverts  in  brickwork  on  the  land  side  of  the  wall,  the  numbers  of 
these  culverts  being  gradually  reduced  and  their  dimensions  in- 
creased as  they  approach  the  junction  with  the  large  sewer. 

HIGH-PRESSURE   GEARED   PUMPING   ENGINES. 

Small  high-pressure  geared  engines  may  be  conveniently  used  for 
pumping  water  out  of  docks,  and  for  other  drainage  purposes,  being 
arranged  for  three  pumps.  The  connecting  rod  runs  from  the  cross- 
head  of  the  piston  rod,  and  works  a  cranked  shaft,  having  a  fly  wheel 
at  one  side  and  pinion  at  the  other,  geared  into  a  spur  wheel  keyed 
on  a  cranked  shaft  for  the  middle  pump ;  one  of  the  side  pumps 
is  worked  from  a  pin  let  into  one  of  the  arms  of  the  spur  wheel,  and 
the  other  pump  is  driven  from  a  crank  placed  on  the  other  end  of 
the  shaft.  The  engine  is  placed  horizontally,  and  the  pumps  are 
vertically  arranged  against  the  side  of  the  dock  wall.  When  they 
are  needed  to  pump  the  water  out  of  a  dock  in  course  of  construc- 
tion, the  engine  is  bedded  on  an  overhanging  wooden  frame,  having 
a  strut  let  into  the  wall,  or  temporary  pile  foundation,  on  each  side 
of  the  frame  for  carrying  the  engine  and  the  three  throw  cranks  for 
the  pumps.  The  pumps  are  in  some  instances  of  the  plunger  type, 
having  the  plungers  cast  in  brass;  while  others  are  simply  lift  pumps, 
fitted  with  valves  of  india  rubber  working  on  brass  gratings.  There 
is  one  suction  pipe  and  one  discharge  pipe  common  to  all  the  three 
pumps;  the  former  has  a  three-branched  pipe  fitted  to  the  top,  to 
which  are  bolted  the  pumps,  one  to  each  branch;  while  the  latter  is 


2^6  MODERN   STEAM   PRACTICE. 

placed  across  the  pumps,  in  communication  with  the  valve  chests, 
having  one  vertical  delivery  pipe  placed  at  the  end. 

THE   CENTRIFUGAL   PUMP. 

Centrifugal  pumps  have  been  much  used  for  pumping  water  out 
of  works  in  course  of  construction,  and  are  recommended  for  their 
simplicity  and  the  ease  with  which  they  can  be  applied  to  almost 
any  situation.  The  pump,  when  placed  in  position,  is  driven  by  a 
belt  from  the  fly  wheel  of  a  portable  engine.  This  is  a  temporary 
arrangement;  but  many  centrifugal  pumps  have  been  fitted  up  of 
a  permanent  kind,  driven  by  wheel  gearing.  When  the  lift  is  of 
moderate  height  these  pumps  throw  a  vast  body  of  water;  and  as 
they  are  not  so  liable  to  get  choked  with  foreign  matter,  they  may 
be  used  in  many  situations  for  pumping  sewage  with  advantage. 

Fig.  149  represents  a  pair  of  centrifugal  pumps  of  the  largest  size 
for  drainage  purposes  connected  directly  to  the  engines,  a  class  of 
machinery  brought  to  great  perfection  by  the  Messrs.  Gwynne  &  Co. 
of  London.  This  description  of  pump  is  admirably  adapted  for 
works  of  construction,  water  works,  graving  docks,  &c.,  and  more 
especially  for  drainage  purposes,  large  tracts  of  land  having  been 
reclaimed  by  its  aid. '  Where  low  lifts  only  are  required  it  far  eclipses 
the  ponderous  pumping  engine  of  the  beam  type. 

The  construction  of  this  pump  is  very  simple.  The  revolving 
wheel  or  disc  is  formed  of  two  concave  plates,  placed  parallel  with 
their  concave  surfaces  towards  each  other.  Two  saucers,  placed 
in  corresponding  positions,  will  give  an  idea  of  the  arrangement. 
Between  these  discs  is  an  arm  or  impeller,  radiating  from  a  boss  or 
hollow  axis,  mounted  on  a  shaft  which  works  horizontally,  vertically, 
or  at  any  intermediate  angle.  This  impeller,  which  regulates  the 
distance  between  the  discs,  varies  in  breadth;  its  narrowest  part  is 
at  the  outer  edge  of  the  discs,  becoming  gradually  broader  until 
its  edge  intersects  the  inner  surface  of  the  openings  for  the  suc- 
tion. Its  breadth  is  varied  in  such  a  ratio  that  the  areas  of  any 
section  cut  from  the  wheel  by  the  surfaces  of  circular  cylinders, 
whose  axes  coincide  with  that  of  the  shaft,  shall  be  equal  to  such 
other  section  at  any  distance  from  the  centre ;  and  these  areas  are 
so  arranged  in  order  that  the  column  of  water  or  other  fluid  enter- 
ing the  wheel  when  in  a  state  of  revolution  may  have  an  uninter- 
rupted flow  from  the  centre  to  the  circumference,  and   that  the 


STATIONARY   ENGINES. 


237 


quantity  received  and  discharged  may  be  constantly  equal.  This 
is  considered  to  be  essential  when  large  bodies  of  water  are  to  be 
discharged,  or  when  high  velocities  are  required.  The  inner  surfaces 
of  the  discs,  or  the  annular  opening  around  the  whole  circumference, 


Fig.  149. — Arrangement  of  Centrifugal  Pumping  Machinery — Gwynne  &  Co. 

has  an  area  equal  to  the  openings  at  which  the  water  is  admitted 
into  the  centre  of  the  revolving  wheel.  There  are  two  cylinders 
or  water  passages,  one  on  each  side,  with  a  passage  for  each  in 
connection  with  one  suction  pipe,  rendering  the  pump  extremely 


2^S  MODERN   STEAM    PRACTICE. 

compact  In  one  of  the  cylinder  covers  or  ends  there  is  a  bear- 
ing supporting  the  spindle  on  which  the  wheel  is  fixed,  in  the 
other  cylinder  cover  there  are  a  gland  and  stuffing  box  through 
which  the  shaft  for  the  revolving  wheel  passes.  The  suction  pipe 
may,  if  desired,  be  run  any  moderate  length  horizontally,  and  the 
pump  may  be  placed  from  15  to  20  feet  vertically  above  the  water 
to  be  raised ;  in  most  cases  it  is  advisable  to  have  a  foot-valve  at 
the  bottom  of  the  suction  pipe,  so  as  to  retain  the  water  in  the 
pump  when  standing  still.  The  delivery  pipes,  as  seen  in  Fig.  149, 
are  fitted  with  self-acting  flap  valves,  to  prevent  any  water  flowing 
back  on  to  the  land  when  the  pump  is  not  working.  The  pumps  are 
fitted  to  discharge  30,000  gallons  per  minute,  12  feet  high;  the  pipes 
are  42  inches  in  diameter;  the  engines  are  of  the  horizontal  condens- 
ing type;  diameter  of  cylinders  21  inches,,  length  of  stroke  21  inches. 

The  action  of  the  pump  is  as  follows: — The  pump  and  pipes 
being  filled  with  water,  which  the  foot  valve  at  the  bottom  of  the 
suction  pipe  retains,  the  wheels  or  discs  are  coupled  to  the  engine, 
and  the  latter  being  started  at  a  high  velocity,  a  centrifugal  motion 
is  given  to  the  wheel,  and  to  the  water  contained  in  the  disc,  which 
is  driven  out  into  the  case  or  receiver  of  the  pump.  The  partial 
vacuum  thus  formed  in  the  disc  is  filled  by  the  water  forced  up  the 
suction  pipe  by  the  pressure  of  the  atmosphere;  the  water  entering 
the  disc  receives  centrifugal  motion  in  the  same  way,  and  thus  a 
continuous  stream  is  received  into  and  discharged  from  the  pump. 
To  prevent  the  water  from  rotating  in  the  case,  and  to  give  it  a 
direction  upwards  to  the  discharge  pipe,  a  stop  or  plate  is  placed  at 
the  base  of  that  pipe,  reaching  to  the  joint  between  the  piston  and 
the  case.  The  joints  between  the  suction  pipes  and  disc  are  so  made 
that  sand,  mud,  or  gritty  matter  cannot  lodge  near  them,  by  which 
means  the  wear  is  so  reduced  as  to  become  almost  imperceptible. 

The  following  may  be  enumerated  as  the  principal  advantages 
of  the  centrifugal  pump: — (i.)  It  can  be  erected  easily  and  quickly. 
(2.)  It  works  with  an  easy  rotary  motion,  without  valves,  eccentrics, 
or  other  contrivances,  which  consume  power  in  friction.  (3.)  It  will 
discharge  a  quantity  of  water  greater  in  proportion  to  the  power 
employed  than  any  other  pump — 75  per  cent,  being  taken  as  an 
average.  (4.)  It  is  economical  in  use,  and  of  very  great  durability 
— an  important  point  in  all  machinery.  (5.)  It  discharges  a  con- 
tinuous and  steady  stream  without  air  vessels.  (6.)  It  is  little 
affected  by  sand,  mud,  grit,  or  other  foreign  matter  in  the  water, 


STATIONARY   ENGINES.  239 

which  so  rapidly  destroy  all  other  pumps.  (7.)  The  large  sizes  will 
admit  the  passage  of  solid  bodies  6  inches  in  diameter  without 
injury,  and  the  smaller  sizes  in  proportion.  (8.)  It  will  pump  hot 
or  cold  liquids  equally  well.  (9.)  It  requires  a  very  light  and  inex- 
pensive foundation,  as  there  is  no  vibration  while  working. 

A  striking  proof  of  the  great  superiority  of  these  noiseless  machines, 
working  at  a  high  speed,  over  the  beam  pumping  engine,  may  be 
seen  in  the  draining  of  the  Haarlem  Lake.  The  weight  of  the 
pumps  and  valves  attached  to  one  of  these  latter  engines  was  about 
200  tons,  the  pumps  were  adapted  to  raise  about  70  tons  of  water 
per  minute  a  height  of  15  feet  when  working  their  usual  speed  of 
eight  or  ten  strokes ;  but  a  centrifugal  pump  of  the  above  descrip- 
tion, doing  the  same  amount  of  work,  will  weigh  only  5  tons. 

The  PiUsometer  Pump  has  been  recently  introduced  with  good 
results  in  many  situations  where  other  forms  of  pump  would  have 
been  more  troublesome  to  keep  in  order.  It  is  a  steam  pump  with- 
out moving  parts  except  certain  valves.  The  operation  consists  in 
forcing  water  to  a  height  by  the  direct  pressure  ot  the  steam,  and 
the  lifting  of  the  supply  into  the  pump  by  the  after  condensation  of 
the  same  steam ;  this  is  accomplished  through  the  medium  of  a  ball 
valve  above  and  clack  valves  below,  arranged  in  two  vertical 
chambers. 


WINDING    ENGINES. 


In  modern  practice  the  use  of  the  flat  hempen  ropes  with  these 
engines  has  been  discarded,  in  favour  of  the  wire  rope  of  a  round 
form.  The  drums  and  pulleys  for  these  ropes  must  be  of  large 
diameter,  and  the  angle  of  the  rope  from  the  drum  to  the  pulley  on 
the  pit-head  frame  should  not  be  too  acute.  Where  the  weight 
lifted  is  about  i  ton,  the  thickness  of  rope  will  be  about  i^  inch, 
and  will  weigh  about  41^  lbs.  to  the  foot,  the  diameters  of  drum  being 
about  5  feet  and  16  feet,  and  the  time  taken  to  lift  through  from 
250  to  300  fathoms  about  i  minute. 

The  engines  used  at  collieries  for  winding  purposes  should  be  of 
the  simplest  construction,  strong,  and  free  from  all  unnecessary 
and  expensive  complications.  With  this  view  spur  gearing  has 
been  discarded  by  many  first-class  manufacturers,  although  geared 
engines  are  still  in  extensive  use:  the  object  of  using  a  pinion  on  the 
engine  shaft  working  into  a  spur  wheel  on  the  drum  shaft  being  to 


240  MODERN   STEAM   PRACTICE. 

reduce  the  diameter  of  the  cylinder  and  length  of  stroke  of  the 
piston,  and  so  to  drive  the  engine  shaft  at  a  greater  number  of 
revolutions  than  the  drum  shaft.  The  old  type  of  engine  most  in 
favour  is  of  the  beam  description,  vibrating  on  a  gudgeon  on  pillow 
blocks  supported  by  a  single  column,  having  plain  cast-iron  guides, 
with  crosshead  and  link  attachment  connecting  the  piston  rod  with 
one  end  of  the  beam  ;  this  being  the  simplest  arrangement  for  giving 
a  true  vertical  motion  to  the  piston  rod.  The  other  end  of  the  beam 
is  connected  to  the  crank  shaft  by  a  cast-iron  connecting  rod,  of 
sufficient  weight  to  balance  the  piston  and  its  adjuncts.  These 
rods  are  fitted  with  wrought-iron  straps  and  brass  bushes,  with  jibs 
and  keys  for  adjusting  the  brasses.  The  bed  plate  for  carrying  the 
cylinder,  main  column,  and  pillow  block  for  the  crank  shaft  is  cast 
in  one  piece.  When  the  bed  plate  is  securely  bolted  down  on  an  even 
surface,  with  a  firm  foundation,  this  form  of  engine  is  very  strong  and 
durable,  and  is  generally  constructed  on  the  high-pressure  principle. 
Horizontal  geared  engines,  however,  have  in  a  great  measure 
superseded  those  of  the  vibrating  beam  type.  They  are  certainly  very 
corr>pact,  and  when  properly  proportioned  give  great  satisfaction, 
notwithstanding  the  objections  arising  from  their  wheel  gearing. 

The  DIRECT-ACTING  HORIZONTAL  ENGINE,  with  the  drum  for 
the  wire  rope  placed  on  the  crank  shaft,  may  be  regarded  as  the  type 
of  engine  to  be  used  for  the  future.  Simplicity  is  the  object  to  be 
attained,  and  we  attain  it  in  the  direct  motion  of  this  engine  simply 
by  giving  a  little  more  diameter  of  cylinder  and  a  longer  piston 
stroke,  with  a  certain  number  of  revolutions  to  suit  the  diameter 
of  the  drum  and  the  speed  usually  allowed  for  running  the  wire 
ropes.  Although  single  engines  are  in  daily  use,  they  are  better  to 
be  used  in  duplicate,  with  one  crank  shaft,  and  cranks  at  right 
angles  to  each  other.  With  the  latter  form  there  is  no  difficulty 
in  starting,  as  is  sometimes  the  case  with  single-cranked  engines, 
which  have  a  tendency  to  stop  on  the  dead  centre,  or  extreme  end 
of  the  stroke,  and  require  great  attention  on  the  part  of  the  attend- 
ant to  prevent  this  occurring.  This  objection  is  entirely  removed 
by  coupling  the  engines  at  right  angles,  the  one  assisting  the  other 
in  the  extreme  position.  The  perfect  ease  and  certainty  with  which 
these  engines  can  be  handled  by  means  of  the  beautiful  link  motion 
and  double  eccentrics — combined  with  the  powerful  brake  on  the 
periphery  of  the  fly  wheel — renders  the  direct -acting  horizontal 
engine  a  great  boon  to  the  practical  miner. 


STATIONARY   ENGINES. 


241 


The  cylinder  for  these  engines  is  a  plain  casting,  with  steam  and 
exhaust  ports  suited  for  the  ordinary  sHde  valve:  one  steam  port 
at  each  end,  and  a  central  port  for  the  exhaust.  It  is  preferable  to 
fit  a  cover  at  each  end,  more  especially  for  large  diameters,  as  the 
boring  bar  requires  to  be  of  a  large  size  to  bore  out  truly  these  long 


Fig.  150.  -  Colliery  Winding  Engines.     Side  Elevation  and  Ground  Plan. 


cylinders  free  from  vibration,  and  the  hole  for  the  bottom  bush  in 
the  stuffing  box  on  a  solid  end  is  too  small  in  diameter  for  an 
ordinary  sized  boring  bar.  There  is  a  deep  stuffing  box  on  each 
cover,  fitted  with  a  gland  in  the  usual  manner.  The  piston  rod 
passes  through  both  these  boxes,  an  arrangement  which  takes  part 

16 


242  MODERN    STEAM   PRACTICE. 

of  the  weight  off  the  piston  on  the  end  glands,  the  piston  rod  acting 
as  a  round  beam  loaded  at  the  middle  when  the  piston  is  at  half 
stroke;  by  this  means  the  action  of  the  piston  has  not  so  much 
tendency  to  wear  the  cylinder  oval.  Trunks  or  hollow  pipes  have 
been  introduced  in  some  classes  of  blowing  engines  to  remedy  this 
evil,  inherent  in  all  horizontal  engines  of  very  large  size;  and  when 
properly  proportioned  they  have  given  good  results.  The  cylinder 
is  cast  with  brackets  on  the  bottom  half  for  bolting  it  down  on  the 
bed  plates;  of  course  these  palms  or  brackets  should  be  nearly  in  a 
line  with  the  strain,  or  a  little  below  the  centre  line  of  the  cylinder. 
Joggles  are  cast  on  the  bed  plate  to  embrace  the  brackets,  and  by 
this  means  end  keys  are  fitted  and  driven  in  tightly,  thus  taking 
the  shearing  strain  off  the  bolts.  By  attention  to  these  details  secure 
and  firm  work  is  obtained,  more  especially  for  high-pressure  engines, 
where  the  succession  of  shocks  from  the  high  steam  pressure  used 
has  a  great  tendency  to  shake  the  cylinder  and  loosen  the  fittings 
if  not  properly  joggled  to  the  bed  plate.  Indeed,  for  fast-going 
engines  of  the  high-pressure  type,  the  repeated  shocks  received  on 
the  end  of  the  cylinder  necessitates  the  use  of  wrought-iron  stays 
to  bind  the  cylinder  and  bed  plate  firmly  together;  some  makers 
even  casting  the  cylinder  along  with  the  bed  plate,  which  effectually 
secures  this  object. 

The  steam  valve  is  an  ordinary  D  one,  and  should  be  fitted  with 
packing  rings  on  the  back,  bearing  on  the  valve-casing  cover.  Some 
makers,  however,  prefer  a  small  piston  working  in  a  short  cylinder 
placed  on  the  valve-casing  cover,  the  piston  being  connected  to  the 
valve  by  means  of  a  vibrating  link.  Some  such  contrivance  is 
absolutely  necessary  to  take  the  back  pressure  off  the  valve ;  and 
the  former  method  does  so  by  reducing  the  area  on  the  back  of 
the  valve — that  is  to  say,  the  rings  are  made  steam  tight,  and  the 
surface  exposed  to  the  steam  in  the  casing  is  reduced ;  while  by  the 
latter  method  the  valve  is  drawn,  as  it  were,  off  the  face  with  a 
certain  force  applied  by  means  of  the  piston,  and  which  being 
received  on  the  pins  of  the  vibrating  link,  renders  it  comparatively 
easy  to  move  the  valves  by  hand,  just  as  any  heavy  weight  is  easily 
moved  when  suspended  by  a  chain.  The  valve  casing  is  sometimes 
cast  on  the  cylinder;  but  many  prefer  it  to  be  separate,  and  secured 
with  bolts,  as  in  this  case  the  facing  for  the  valve  is  more  readily 
planed,  and  afterwards  scraped  to  a  true  surface.  The  usual 
stuffing  box  is  cast  along  with  the  casing,  with  brass  bush  and 


STATIONARY   ENGINES.  243 

gland,  and  it  should  have  a  brass  guiding  socket  at  the  other  end 
for  taking  the  valve  spindle,  which  passes  through  a  tube  cast  along 
with  the  valve,  and  to  which  it  is  secured  by  means  of  a  nut  and 
jam  nut  at  each  end.  Some  makers  dispense  with  this  guide,  and 
attach  the  rod  to  the  valve  by  a  screwed  part  at  its  end,  having  a 
nut  let  into  the  valve,  with  a  jam  nut  to  lock  it  securely  when  the 
valve  is  properly  set. 

The  valve  is  actuated  by  double  eccentrics  and  link  motion. 
The  eccentric  sheaves  are  of  cast  iron,  of  the  usual  construction, 
and  may  be  cast  all  in  one  piece,  or  have  the  means  of  taking  them 
off  the  shaft  without  disturbing  the  main  parts  of  the  engine.  The 
straps  should  be  cast  in  brass,  or  they  may  be  forged  on  the  eccen- 
tric rods,  and  lined  with  strips  of  brass  rivetted  on.  The  link, 
suspension  rods,  weigh  shaft,  and  reversing  handle  should  be  made 
of  wrought  iron,  and  all  the  working  pins  case-hardened ;  and  the 
sliding  block  for  the  link  should  be  of  steel.  All  the  bearings  for 
the  weigh  shaft  should  be  bushed  with  brass,  and  the  whole  motion 
adjusted  in  a  strong  and  substantial  manner. 

The  starting  handle  should  be  a  plain  lever,  fitted  with  quadrant 
and  catch  for  holding  the  link  in  position.  The  starting  platform 
should  be  placed  so  as  to  command  a  good  view  of  the  pit  head. 
Its  position  depends,  of  course,  on  the  method  of  fitting  up  the 
machinery,  but  in  ordinary  cases  the  platform  may  be  arranged  at 
the  back  of  the  winding  drum,  and  of  sufficient  height  to  see  well 
over  it.  In  this  position,  when  the  fly  wheel  is  placed  at  the  centre 
of  the  engine  shaft,  the  friction  strap  and  hand  gear  for  working  it 
is  greatly  simplified,  and  the  attendant  has  the  two  important  handles 
for  reversing  and  applying  the  friction  brake  in  a  direct  line  with 
the  pit  head.  The  handle  for  working  the  stop  valve  of  the  equili- 
brium type  should  be  placed  here  likewise,  on  the  centre  of  the 
steam  pipe  between  the  two  engines.  The  handles  are,  however, 
at  times  arranged  on  the  outside  of  the  left-hand  engine  looking 
towards  the  pit  head,  with  a  cross  shaft,  as  in  the  former  method, 
for  the  reversing  gear  placed  underneath  the  bed  plates  or  above 
them,  supported  at  the  end  and  middle  with  suitable  pillow  blocks. 
On  this  shaft  the  lifting  arms  are  fitted,  with  a  weight  arm  at  the 
centre  of  the  shaft,  or  between  the  end  and  middle  pillow  block, 
having  a  suitable  weight,  which  may  be  placed  on  the  starting 
handle,  for  balancing  the  links  and  rods,  and  thus  easing  the  labour 
of  starting  and  reversing  the  engines.     The  handle  will  of  course 


244  MODERN    STEAM    PRACTICE. 

suit  almost  all  attendants  when  arranged  for  the  right  hand.  The 
lever  for  the  brake  is  worked  by  foot ;  it  should  be  of  great  length, 
and  so  placed  that  the  attendant  can  press  it  with  his  left  foot 
whilst  he  holds  the  reversing  handle.  The  brake  lever  must,  of 
course,  be  arranged  horizontally,  and  fitted  with  a  cross  shaft  and 
short  lever  at  the  end  for  taking  the  brake  strap  of  wrought  iron 
lined  with  blocks  of  wood.  The  shaft  is  supported  on  three  pillow 
blocks,  and  is  fitted  with  a  weighted  lever,  the  weight  being  suffi- 
cient to  balance  the  long  foot  lever,  which  should  have  a  suitable 
stop  to  keep  it  always  at  a  convenient  height  for  treading  upon. 
Many  engineers  are  of  opinion  that  it  would  be  better  to  fit  a  hand 
lever  and  rod  to  the  long  brake  arm,  instead  of  pressing  on  it  with 
the  foot ;  but  it  must  be  borne  in  mind  that  both  hands  may  be 
required  at  times  to  lift  or  depress  the  link  motion,  and  the  foot 
can  be  applied  to  the  brake  when  the  engine  requires  to  be  sud- 
denly stopped.  In  other  examples  the  long  brake  handle  is  placed 
above  the  floor  of  the  engine  room,  the  engineman  moving  it  by 
hand,  and  the  handle  is  kept  up  by  a  catch  cast  on  a  suitable  cast- 
iron  column:  there  is  another  catch  placed  on  a  nut  worked  by  a 
screwed  rod  and  wheel,  supported  by  the  column.  The  nut  can  be 
adjusted  at  pleasure  to  suit  the  wear  of  the  wooden  friction  blocks. 
When  the  handle  is  depressed  and  sprung  under  the  catch  the 
blocks  are  pressed  against  the  friction  wheel,  and  when  the  friction 
requires  to  be  increased  the  wheel  on  the  screw  rod  is  turned  by 
hand,  which  firmly  locks  the  friction  blocks. 

The  piston  for  all  horizontal  engines  should  be  of  the  strongest 
and  lightest  construction  possible,  fitted  with  a  single  packing  ring, 
and  the  usual  junk  ring.  The  packing  ring  may  have  steel  springs 
between  it  and  the  body  of  the  piston ;  but  some  makers  prefer  a 
plaited  gasket.  The  junk  ring  is  bolted  to  the  piston  with  screwed 
bolts  and  nuts  recessed  in  the  body  of  the  piston.  Another  form 
of  piston  largely  used  for  high-pressure  engines  is  a  plain  casting, 
turned  on  the  rubbing  surface,  and  recessed  for  light  steel  springs. 
This  is  certainly  the  simplest  form  of  metallic  packed  piston ;  and 
when  it  is  supported  by  means  of  the  piston  rod  passing  through 
stuffing  boxes  at  each  end  of  the  cylinder,  it  works  admirably  even 
for  large  diameters.  The  method  of  connecting  the  piston  to  the 
rod  is  by  forming  a  coned  part  at  the  middle  of  the  rod  with  a 
corresponding  cone  turned  in  the  piston,  which  is  secured  by  a 
cotter  passing  through  the  body  of  the  piston,  as  in  the  ordinary 


STATIONARY   ENGINES.  245 

packing-ring  system;  but  when  the  piston  is  cast  solid,  and  indeed 
for  all  pistons,  it  is  preferable  to  cut  a  screw  on  the  rod  at  the 
small  end  of  the  cone,  which  is  fitted  with  a  nut  for  pressing  the 
piston  firmly  on  the  cone ;  and  to  prevent  the  piston  turning  round 
in  the  cylinder,  as  it  may  do  in  course  of  time,  a  small  short  key  is 
let  into  the  rod,  having  a  corresponding  part  cut  in  the  piston  for 
its  reception. 

The  crosshead  and  gudgeon  for  the  connecting  rod  is  of  wrought 
iron,  suited  for  single  or  forked  ends  as  may  be  desired ;  the  hole  in 
the  crosshead  for  the  piston  rod  is  bored  out  slightly  tapered,  the 
rod  being  turned  to  suit,  and  secured  with  a  cotter  passing  through 
them  both.  Holes  should  be  drilled  at  the  small  end  of  the  cotter 
for  passing  a  split  pin  through,  to  keep  it  from  shaking  loose.  The 
holes  for  the  gudgeon  in  the  jaws  of  the  crosshead  are  bored  quite 
parallel,  and  the  gudgeon,  being  accurately  turned,  is  driven  through 
tightly,  and  secured  with  a  key.  The  gudgeon  can  be  of  a  less 
diameter  at  the  ends  for  taking  the  guide  blocks,  and  of  sufficient 
length  at  one  end  for  fitting  the  eye  of  the  feed-pump  plunger  to  it. 

The  motion  bars  for  guiding  the  crosshead  in  a  direct  line  with 
the  piston  rod  are  of  cast  iron.  The  bottom  bars  are  generally  cast 
along  with  the  bed  plate,  but  they  sometimes  form  separate  castings, 
which  require  to  be  fitted  to  the  bed  plate;  while  the  top  bars  are 
generally  made — so  that  the  gear  can  be  adjusted — with  thin  strips 
of  metal  between  them  and  the  bottom  bars,  which  can  be  reduced 
in  thickness  as  the  guide  blocks  wear.  In  this  arrangement  the  top 
bars  are  secured  to  the  bottom  ones  with  bolts  at  the  ends,  the  same 
bolts  securing  the  bottom  bars  to  the  bed  plate ;  but  in  some  cases 
the  bottom  and  top  motion  bars  are  cast  in  one  piece,  and  fitted 
and  bolted  down  on  the  bed  plate.  These  guiding  bars  must  be 
accurately  planed,  and  also  the  guide  blocks,  which  are  cast  in  hard 
brass.  Sometimes  cast-iron  blocks  are  adopted,  in  which  case  the 
rubbing  surfaces  are  filled  in  with  white  metal,  recesses  being 
left  in  the  casting  for  that  purpose ;  plain  cast-iron  blocks,  however, 
answer  very  well,  when  lubrication  is  properly  attended  to — that 
being  a  most  important  point  in  all  rubbing  surfaces.  Oil  cups 
should  be  cast  on  the  top  motion  bars,  and  fitted  with  proper  covers 
to  exclude  grit,  with  siphon  pipe  and  wick  to  supply  the  oil  drop 
by  drop. 

The  connecting  rod  is  of  wrought  iron,  turned  from  end  to  end, 
with  oblong  pieces  at  the  ends  accurately  planed,  and  fitted  with 


246  MODERN    STEAM   PRACTICE. 

wrought -iron  straps  and  jibs  and  keys  for  adjusting  the  brass 
bushes ;  suitable  lubricating  cups  are  fitted  to  the  straps. 

The  main  cranks  are  of  cast  iron,  but  most  engineers  would 
prefer  them  of  wrought  iron,  as  they  are  much  stronger  and  better 
adapted  for  engines  subjected  to  severe  shocks.  They  are  usually 
bored  out  and  shrunk  on  the  shafts  hot ;  but  when  they  are  forced 
on  cold  with  an  hydraulic  ram  the  material  is  not  so  much  strained, 
while  the  holding  power  is  equally  good.  The  cranks  are  further 
secured  with  a  single  key,  fitting  into  a  recess  planed  in  the  shaft 
and  slotted  out  in  the  crank  eye.  The  crank  pin  is  slightly  tapered 
in  that  part  fitting  into  the  hole  in  the  crank,  and  is  forced  on  and 
then  rivetted  at  the  end,  a  part  being  turned  out  for  this  purpose; 
this  makes  very  secure  work.  In  some  recent  examples  the  cranks 
are  formed  of  discs  of  cast  iron,  with  a  side  flange  on  the  circum- 
ference of  the  disc,  strongly  ribbed  to  the  boss  at  the  centre.  This 
plan  balances  the  engine  better  than  the  single  crank  arm.  The 
crank  pin  is  secured  by  means  of  a  nut  and  feather  or  key  on  the 
pin. 

The  main  pillow  blocks  are  separate  castings,  fitted  with  brasses, 
and  caps  arranged  at  an  angle,  so  that  the  brasses  are  adjusted  in 
the  direction  of  the  greatest  strain.  The  bottom  of  the  blocks  are 
planed,  as  also  the  fitting  strips  on  the  bed  plate,  which  has  extra 
strong  jog'gles  cast  on  it  for  driving  in  wedges,  thus  taking  the 
shearing  stress  off  the  pillow  block  holding-down  bolts. 

The  bed  plate  is' a  strong  frame  of  a  box  section,  open  at  the 
bottom ;  it  is  tied  at  the  ends  and  at  the  middle  in  the  casting,  and 
should  be  strengthened  with  cross  feathers  between  the  sides,  having 
all  the  necessary  joggles  and  fitting  strips  for  the  cylinder,  pillow 
block,  pumps,  and  other  minor  fittings.  There  should  be  at  least 
four  large  holding-down  bolts  on  each  side  of  the  frame,  passing  down 
through  holes  left  in  the  foundation,  and  secured  on  the  under  side 
with  a  plate  and  key  for  each  bolt.  The  foundations  should  con- 
tain suitable  man-holes,  so  that  these  bolts  can  be  adjusted  at  any 
time.  In  some  instances  the  plates  at  the  bottom  of  the  foundation 
are  carried  across,  embracing  two  bolts ;  by  this  means  a  foundation 
of  brickwork  laid  in  cement  is  firmly  bound  from  top  to  bottom. 
When  brick  is  used  for  the  foundation  it  is  preferable  that  a  layer 
of  stone-work  or  balks  of  wood  be  placed  on  the  top,  for  the  main 
bed  plate  to  rest  on. 

The  main  shaft  of  the  engine  should  be  of  wrought  iron,  and  all 


STATIONARY   ENGINES.  247 

the  bearings  and  raised  parts  for  the  drum,  fly  wheel  if  so  fitted, 
eccentrics,  and  other  minor  details,  should  be  accurately  turned; 
while  all  the  eyes  of  the  various  fittings  should  be  bored  out  to 
the  exact  size,  and  held  by  means  of  keys  bearing  on  a  flat  part  of  the 
shaft,  keyways  being  cut  in  the  parts.  This  is  by  far  the  cheapest 
and  best  mode  of  hanging  the  drum  and  centre  pieces,  fly  wheel, 
&c.;  the  old  mode  of  hanging  these  fittings  with  a  number  of  keys 
in  each  is  not  to  be  commended,  and  has  now  become  obsolete. 

The  feed  pump  is  of  the  plunger  type,  and  is  bolted  down  on 
the  top  of  the  bed  plate  at  the  end  nearest  the  main  crank  shaft. 
It  is  desirable  that  the  plunger  should  be  of  brass  or  Muntz  metal, 
connected  by  means  of  a  wrought-iron  rod  to  the  end  of  the  gudgeon 
for  the  crosshead — an  eye  is  forged  on  this  rod,  and  accurately 
bored  out  to  take  the  end  of  the  gudgeon,  and  held  in  position  with 
a  set  screw.  When  the  pump  is  placed  well  back,  the  plunger  is 
better  balanced  at  the  extreme  IN  stroke,  as  there  is  a  considerable 
distance  from  the  pump  gland  to  the  centre  of  the  crosshead  while 
in  that  position ;  and  the  plunger  by  this  arrangement  is  not  so 
liable  to  droop,  as  it  would  do  were  the  crosshead  working  quite 
close  up  to  the  pump  gland.  The  suction  and  delivery  valves  and 
seatings  are  of  brass,  fitted  into  cast-iron  valve  chests ;  an  escape 
valve  should  also  be  fitted,  loaded  with  a  certain  weight,  so  that 
when  the  attendant  shuts  the  feed  valve  on  the  boiler,  the  water  is 
forced  past  the  escape  valve,  and  finds  its  way  by  a  pipe  connection 
into  the  pond  or  cistern  from  which  the  supply  is  drawn.  An  air 
chamber  should  be  fitted  to  some  convenient  part  of  the  feed  pipe, 
as  by  this  means  the  flow  is  more  uniform,  and  tends  to  lessen  the 
vibration  in  the  pipes  when  the  engine  is  working  at  full  speed. 
As  these  pipes  are  sometimes  subjected  to  the  influence  of  hard 
frost,  the  engine  rarely  going  all  night,  they  should  be  properly 
clothed  and  protected  with  a  non-conducting  material;  and  a  small 
plug  tap  should  be  fitted,  so  that  all  the  water  may  be  run  off 
between  the  pump  and  feed  valve  placed  on  the  boiler:  these  pre- 
cautions taken,  there  is  no  fear  of  breakage  occurring,  as  has  too 
often  been  the  case  otherwise;  for  when  an  engine  is  started  in  the 
morning  with  the  water  in  the  feed  pipe  frozen  a  fracture  must 
take  place.  In  many  arrangements  the  feed  pump  is  dispensed 
with,  the  boilers  being  fed  with  a  separate  steam  pump.  The  steam 
pipes  must  also  be  protected  with  felt  and  canvas  sewn  over,  to 
prevent  condensation.     The  exhaust  pipe  (when  the  waste  steam 


248  MODERN    STEAM   PRACTICE. 

is  blown  up  the  chimney)  should  be  trapped  at  the  end,  by  leading 
it  into  a  cast-iron  cistern,  fitted  with  a  separate  pipe  into  the 
chimney,  having  a  bend  at  the  end  for  directing  the  waste  steam 
vertically;  by  this  means  much  of  the  moisture  is  got  rid  of,  being 
retained  in  the  cistern  and  run  off  by  a  suitable  overflow  pipe.  In 
this  way  the  chimney  is  kept  comparatively  dry,  and  consequently 
less  liable  to  the  deterioration  caused  by  a  blast  of  steam  and  water 
blown  into  it.  Some  engineers  prefer  blowing  off  the  waste  steam 
directly  from  the  cylinder  by  a  vertical  pipe  passing  through 
the  roof  of  the  engine  house.  By  such  an  arrangement  there  is,  of 
course,  no  steam  blast  to  injure  the  chimney;  but,  on  the  other 
hand,  we  lose  its  valuable  aid  in  urging  the  fires,  by  causing  a 
partial  vacuum  in  the  chimney,  which  tends  to  supply  through  or 
between  the  fire  bars  the  necessary  quantity  of  oxygen  to  effect 
complete  combustion. 

The  drums  for  the  round  wire  ropes  must  be  of  large  diameter. 
They  are  of  two  kinds,  conical  and  parallel ;  with  the  conical  the 
strain  on  the  engines  is  better  regulated.  The  lift  is  taken  on  the 
smallest  diameter,  and  the  rope  unwinds  for  the  empty  cage  from 
the  largest  diameter;  consequently  the  latter  balances  in  a  measure 
the  ascending  cage  fully  loaded,  which  is  lifted  slowly,  throwing 
less  strain  on  the  machinery.  The  drums  are  constructed  of  light 
cast-iron  wheels,  each  with  eight  strong  arms,  and  arranged  for 
bolting  together  in  two  halves;  a  side  flange  is  cast  on  to  receive  the 
wooden  battens,  to  which  they  are  securely  bolted.  For  the  conical 
drums  there  are  two  wheels  of  the  same  diameter,  one  at  each  end, 
with  flanges  bevelled  according  to  the  hollow  given  to  the  cone, 
and  a  smaller  wheel  is  placed  between  them,  having  a  flat  rim ;  the 
wood  is  laid  quite  flat  on  the  inside,  and  for  the  outer  diameter  it  is 
cut  to  the  cone  required.  The  wire  ropes  are  put  on  one  above 
and  another  below  the  drum,  and  are  wound  from  its  longitudinal 
centre,  the  cone  increasing  to  the  ends  at  each  side.  The  side  and 
middle  sheaves  are  keyed  on  the  shaft  similarly  to  an  ordinary 
fly  wheel,  and  should  be  fitted  with  wrought-iron  rings,  shrunk  on 
the  outer  circumference  of  the  bosses.  It  is  preferable  to  fit  a  fly 
wheel  close  up  to  the  main  bearing;  it  should  be  of  sufficient  weight 
for  the  engine,  and  made  of  extra  strength  in  the  arms,  as  the 
brake  is  generally  applied  on  the  periphery. 

The  most  approved  form  of  brake  consists  of  wooden  blocks 
fastened  to  wrought-iron  hinge  pieces,  vibrating  on  pins  and  joints, 


STATIONARY   ENGINES.  249 

secured  to  the  floor  in  the  fly-wheel  pit.  There  are  two  fitted 
under  the  wheel  at  each  end.  On  the  vibrating  centre  or  fulcrum 
of  the  long  brake  lever,  a  shaft  carried  on  suitable  bearings  has  a 
double-ended  short  lever  keyed  on  it,  fitted  with  eyes  and  pins; 
from  these  joints  two  side  rods  pass  along,  one  on  each  side  of  the 
fly  wheel,  and  are  secured  to  eyes  on  the  wrought-iron  pieces  for 
taking  the  friction  blocks.  Both  brakes  are  so  fitted,  and  with  a 
movement  of  the  long  lever  the  off-brake  is  drawn  against  the 
periphery  of  the  fly  wheel,  while  the  near  one,  fitted  with  short  rods, 
transmits  a  compressive  strain,  which  of  course  the  short  connecting 
links  are  better  calculated  for.  With  parallel  winding  drums  the 
arrangement  is  somewhat  different.  The  drums  have  two  side 
sheaves  for  each ;  the  two  centre  ones  are  placed  sufficiently  wide 
apart  to  take  a  strong  ring  which  is  fitted  to  the  skeleton  sheaves, 
this  serving  as  a  brake  wheel,  which  in  this  arrangement  is  acted 
on  by  a  strap  lined  with  wood  placed  underneath  it,  fitted  with 
suitable  levers  and  shafts.  Some  authorities  consider  that  this 
brake  wheel  is  not  so  well  placed  as  in  the  former  example,  for  the 
strain  acting  on  the  centre  of  the  shaft  between  the  two  engines 
tends  to  throw  undue  stress  on  the  shaft.  But  we  must  not  lose 
sight  of  the  fact  that  when  a  separate  fly  wheel  is  used,  placed  at 
the  side  of  the  drum,  the  adjoining  bearing  has  more  duty  to  per- 
form, and  it  may  be  concluded  that  with  extra  strength  given  to 
the  shaft,  to  resist  the  pressure  of  the  brake,  the  intermediate  brake 
wheel  can  be  used  with  advantage,  equalizing  the  wear  on  the 
bearings,  which  is  an  important  consideration  in  coupled  engines. 

In  some  examples  where  steam  pumps  are  fitted,  instead  of  the 
usual  feed  pumps,  thus  simplifying  the  engine  considerably,  the  feed 
water  is  heated  in  its  transit  to  the  boilers  by  passing  through  a 
number  of  small  tubes  fixed  in  plates,  inclosed  in  a  cast-iron  cylinder; 
the  exhaust  steam  enters  this  cylinder,  surrounds  the  tubes,  and 
transmits  its  heat  to  the  cold  water  passing  through  them.  Some 
engineers  blow  the  exhaust  steam  into  a  receiver,  and  the  cistern 
placed  at  the  end  of  the  exhaust  pipe  for  collecting  the  condensed 
water  is  a  similar  contrivance:  the  steam  is  blown  over  the  surface 
of  the  water,  which  becomes  thoroughly  heated.  Of  course  the 
steam  that  is  not  condensed  is  blown  up  the  chimney  in  either  of 
those  feed-water  heaters.  In  the  former  plan  there  is  no  trouble 
attending  the  operation,  as  the  feed  water  is  simply  passed  through 
the  small  tubes  in  its  transit  from  the  feed  pumps;  but  the  latter 


250 


MODERN   STEAM   PRACTICE. 


requires  attention  to  keep  the  water  in  the  cistern  at  the  proper 
level,  and  in  many  situations  the  water  would  require  to  be  raised 
by  a  separate  pump,  or  the  cistern  placed  low  enough  to  admit  of 
the  water  running  in  from  an  adjoining  pond. 

We  give  a  Plate  of  a  Winding  Engine  of  approved  construction, 
erected  in  1881  for  a  pit  belonging  to  the  Benhar  Coal  Company, 
at  Niddrie  near  Edinburgh. 


BLOWING   ENGINES. 

OVERHEAD-BEAM   BLOWING   ENGINE. 
We  will  now  consider  that  form  of  engine  used  for  blowing  air  to 
the  furnaces  for  melting  iron  ores,  technically  termed  the  "  blowing 


Fig.  151. — Blowing  Engine.     Side  Elevation. 


engine."  This  engine  delivers  the  air  into  a  receiver,  the  pressure 
varying  from  2  to  4  lbs.  per  square  inch,  or  a  mean  of  say  2/{.  lbs., 
that  being  the  pressure  on  the  large  piston  of  the  blowing  cylinder. 


WINDING    ENGINES. 


IIOlJJ 


iijsiif 


ViTH   DOUBLE   ECCENTRICS.  LINK  MOTION.  AND  TAPPET  VALVE  GEAR. 


STATIONARY   ENGINES. 


251 


A  variety  of  forms  of  blowing  engines  are  now  in  use,  viz.  the 
beam,  the  side-lever,  the  vertical,  and  the  horizontal,  which  we  will 
notice  in  succession. 

The  high-pressure  beam  engine  has  been  largely  used  for  blowing 
purposes.  Its  main  beam  is  cast  in  two  halves,  held  together  by 
distance  pieces;  the  steam  cylinder  is  placed  at  one  end  of  the 
beam,  and  the  blowing  cylinder  at  the  other.  The  connecting  rod 
and  crank  shaft  are  placed  between  the  steam  cylinder  and  the 
main  centre  of  oscillation  of  the  beam,  and  the  cold  water  and 
feed  pumps  between  the  blowing  cylinder  and  the  main  centre  of 
oscillation. 

The  steam  cylinder  is  a  plain 
casting,  with  oblong  branches 
at  the  top  and  bottom  for  the 
steam  ports,  which  are  made 
as  short  as  possible.  When 
the  stroke  of  the  piston  is  long 
it  is  desirable  to  have  the 
steam  valves  so  arranged  that 
the  cubical  capacity  of  the 
passages  on  the  cylinder  side 
should  be  as  small  as  practi- 
cable, by  which  means  much 
steam  is  saved  at  each  stroke, 
as  compared  with  some  ar- 
rangements where  the  pas- 
sages extend  from  the  top  to 

the  bottom  of  the  cylinder.     A  Fig.  iS2.-Steam  CyUnder  and  Cover, 

square  base  is  cast    along  with  a,  Cylinder,     b  b,  steam  ports.     c,Coneplug. 

the  cylinder,  having  a  hole  in 
the  centre  for  the  boring  bar  to 
pass  through,  which  is  afterwards  filled  up  with  a  plug  or  cover.  Part 
of  the  base  is  hollowed  out  on  the  opposite  side  from  that  of  the 
steam  ports,  to  give  the  necessary  clearance  for  the  main  connecting 
rod.  The  body  of  the  cylinder  has  suitable  belts  cast  on,  and  also 
a  projecting  moulding  near  the  top  for  supporting  the  platform. 
The  cylinder  is  firmly  bolted  down  at  each  corner  of  the  base  plate 
with  long  bolts,  passing  down  through  holes  left  in  the  foundations, 
and  secured  at  the  under  end  with  plates  and  cotters;  these  beam 
plates  extend  across  the  structure  from  hole  to  hole.     A  cast-iron 


D,  Cover. 

E,  Raised  lip  on  flange  for  catching  the  oil. 
F,  Part  cut  out  for  the  connecting  rod. 


252  MODERN    STEAM   PRACTICE. 

plate  is  laid  down  on  the  top  of  the  foundation,  having  fitting 
strips  for  correctly  adjusting  the  vertical  line  of  the  cylinder,  cor- 
responding strips  being  left  on  its  base  for  that  purpose.  This 
makes  a  thoroughly  good  fixture,  as  these  foundation  plates  spread 
over  a  large  surface  of  the  stone  or  brick  work,  and  the  action  of 
the  steam  in  the  cylinder  and  motion  of  the  working  parts  have 
not  so  much  tendency  to  abrade  the  stone  and  loosen  the  founda- 
tions. The  cylinder  cover  is  generally  an  open  casting,  and  should 
be  turned  on  the  face ;  the  surface  is  made  steam  tight  by  scraping 
the  faces  on  the  cover  and  cylinder,  and  interposing  a  thin  coating 
of  red  lead  at  the  joint  A  brass  bush  is  fitted  at  the  bottom  of 
the  stuffing  box,  and  also  in  the  cast-iron  gland.  The  flange  of 
the  stuffing  box  has  a  raised  part  round  the  edge,  to  prevent  the 
oil  or  other  lubricant  from  flowing  over  and  dirtying  the  cover. 
The  cover  is  turned  all  over  the  exterior,  and  should  be  finished 
bright,  as  it  is  then  much  more  easily  kept  clean.  The  bolts  for 
the  gland  should  be  cut  with  a  square  thread,  and  have  square  nuts, 
as  hexagonal  nuts  are  not  nearly  so  good  for  parts  requiring  such 
frequent  adjustment. 

The  piston  is  of  the  usual  description,  and   made  very  heavy; 


A  w.-r\^ 


I 

Fig.  153. — Piston  for  Steam  Cylinder. 
A,  Coned  part  for  the  piston  rod.     b.  Junk  ring,     c.  Metallic  packing  ring. 

indeed,  some  engineers  cast  the  body  solid,  with  a  view  to  balance 
the  large  blowing  piston  at  the  other  end  of  the  beam.  The  pack- 
ing ring  should  be  in  one  piece;  some  use  two  rings,  but  this  is  not 
required,  and  is  decidedly  objectionable,  from  the  fact  that  there  are 
then  four  faces  to  be  kept  steam  tight,  whereas  with  one  ring  there 
are  only  two.  The  narrow  junk  ring  is  accurately  turned  on  the 
fitting  strips  and  corresponding  parts  on  the  piston,  and  is  made 
steam  tight  by  scraping  the  surfaces.  The  holding-down  bolts  are 
screwed  into  nuts  recessed  into  the  body  of  the  piston  in  the  usual 
manner.  The  piston  rod  is  secured  to  the  piston  by  means  of  a 
coned  part  turned  on  the  former,  with  a  corresponding  cone  on  the 
latter,  through  which  a  cotter  passes  and  tightly  forces  the  piston 
on  the  coned  part  of  the  rod.     A  better  plan  is  to  fit  a  nut  on  the 


STATIONARY   ENGINES. 


253 


Fig.  154.— Piston  Valve  and 
Cylinder. 

\,  Piston  valve.       B,  Metallic 

packing  rings,     c,  Valve  rod. 

D,  Cylinder  for  valve. 

E,  Slot  holes. 


top  of  the  piston,  having  a  screwed  part  on  the  piston  rod,  in  which 

case  a  recess  needs  to  be  left  in  the  cyhnder  cover  for  the  nut  to 

pass  into,  as  the  piston  works  closely  up  to  the  under  side  of  the 

cover  and  down  to  the  bottom  of  the  cylinder, 

%  inch  of  clearance  being  quite  sufficient  be- 
tween the  piston  and  the  end  of  the  cylinder  at 

the  top  and  bottom. 

The  valves   are  of  the  piston  description, 

fitted  with  metallic   packing  rings  and   junk 

rings,  similar  to  the  main   piston;    and   they 

work  in  short  cylinders  placed  in  the  nozzle 

chest  and  bolted  to  the  main  cylinder.      These 

cylinders  are  cast  with  oblong  ports,  the  bars 

lying  at  an  angle;  by  this  means  the  rings 
on  the  valves  work  more 
evenly,  and  are  not  so 
liable  to  form  ruts  as  they 
would  be  were  the  bars 
placed  vertically.  These 
valve  cylinders  are  pro- 
perly secured  in  the  cas- 
ing, which  is  bored  out  for  their  reception. 
Each  valve  is  connected  with  a  rod  passing 
through  the  centre  of  the  piston,  and  secured 
with  a  collar  on  the  rod  and  a  screwed  part 
fitted  with  a  nut. 

The  nozzle  chest  is  arranged  with  one  central 
pipe,  fitted  with  an  expansion  joint,  and  branch 
pieces  at  the  top  and  bottom  for  bolting  to  the 
branches  on  the  main  cylinder  of  the  engine, 
as  well  as  with  the  main  steam  branch  located 
at  the  top,  so  placed  as  to  pass  well  under  the 
beams  for  supporting  the  platform.  The  steam 
from  the  boiler  is  admitted  into  the  .central 
nozzle  between  the  valves,  while  the  exhaust 
takes  place  on  the  top  edge  of  the  top  valve 

A,  Steam  pipe.     B  B,  Valve  ^nd  thc  bottom  cdgc  of  thc  bottom  valve;  the 

cylinders.  c  c,  Exhaust 

pipes.   D  D,  Expansion  joints,  stcam  from  the  top  passing  through  pipes  on 
each  side  of  the  central  pipe,  which  are  like- 
wise fitted  with  expansion  joints.     The  exhaust  steam  from  the  top 


Fig.  155.  —  Nozzle  Chest  for 
Steam  Cylinder. 


254 


MODERN   STEAM   PRACTICE. 


Fig.  156. — Stoup  and  Linlcs  for  Valve  Motion. 

A,  Valve  rod.      B,  Stoup.     c,  Guide  pipe. 
D,  Strap.     E,  Side  link. 

on  the  end  of  the  pipe  and 


of  the  cylinder  passes  down  these  pipes  on  each  side,  and  they  are 

connected  to  a  cross  pipe  at  the  bot- 
tom, which  carries  away  the  steam 
from  both  ends  of  the  main  cyHnder. 
Two  branch  pieces  are  generally  cast 
on  the  cross  pipe,  for  the  convenience 
of  carrying  away  the  exhaust  on 
either  side,  as  maybe  determined  on; 
of  course  one  of  them  has  a  blind 
flange  when  completed,  A  cover  is 
fitted  to  the  top  nozzle  chest,  and  one 
to  the  bottom  chest,  the  latter  having 
a  short  pipe  turned  on  the  exterior 
surface. 

The  valve  spindle  passes  down  this 
pipe,  and  is  connected  to  a  solid  end 
on  another  pipe  (technically  termed 
the  stoiLp),  by  means  of  a  coned  hole 
a  corresponding  cone  turned  on  the 
valve  spindle,  fitted  with  a  nut  on  the 
end  of  the  rod.  On  the  top  of  the 
stoup  a  stuffing  box  and  gland  is  ar- 
ranged, which  makes  it  steam-tight 
on  the  pipe  that  is  bolted  to  the  cover. 
A  wrought -iron  strap  with  two  side 
pins  is  fitted  on  the  stoup;  these  pins 
take  side  rods  passing  downwards  to 
the  pins  on  the  levers  of  the  weigh 
shaft. 

The  wiper  shaft  is  supported  at 
both  ends  on  bearings,  and  is  fitted 
with  a  strong  cast-iron  lever,  having 
a  pin  for  taking  the  eccentric  rod, 
with  other  two  levers  for  the  rods 
connected  to  the  stoup  for  working 
the  valves.      A  back  balance  lever, 

Fig.  i57.-Wiper  Shaft  and  Levers  for  Valve    ^^tcd  with  a  Suitable    Weight    for   bal- 

Motion.— A,  Wiper  shaft.    B  B,  Levers  for  valve,  ancing     the    ValvCS,    IS    alsO     prOvidcd, 

c.  Balance  lever,     d,  Eccentric  lever.  ....  .   .  ^    , 

and  this  is  cast  along  with  one  01  the 
levers  for  the  stoup  connection ;  while  a  socket  is  left  on  the  double 


A 

J          u 

" n 

B                   1 

\ r 

j_ —    ... 

rl 1 

i 

STATIONARY   ENGINES.  255 

lever  for  the  eccentric  rod  for  the  starting  handle.  These  levers 
should  be  made  very  strong  and  well  feathered,  and  may  be  cast 
along  with  the  shaft,  at  least  those  for  the  stoup  and  balance 
weight,  but  the  eccentric  lever  should  be  made  a  separate  casting 
for  adjustment.  As  the  strain  is  light  a  cast-iron  shaft  and  levers 
may  be  adopted,  when  the  weigh  shaft  is  placed  under  the  floor  of 
the  engine  house  out  of  sight;  but  a  preference  ought  to  be  given 
to  wrought  iron  in  all  valvular  arrangements,  as  the  material  is 
better  adapted  for  any  sudden  strain,  even  although  balance  valves 
are  adopted. 

The  valves  are  actuated  by  means  of  an  eccentric  and  rod.     The 


^?-li g- 


Fig.  158. — Eccentric  and  Rod. 
A,  Eccentric  sheave.     B,  Eccentric  rod  and  strap,     c,  Gab  end. 

eccentric  sheave  is  so  arranged  that  it  can  be  put  on  and  taken  off 
the  main  crank  shaft  without  disturbing  any  other  detail,  and  is 
,  secured  on  the  shaft  with  a  key,  as  these  engines  only  require  to 
be  worked  in  one  way,  The  eccentric  rod  is  of  wrought  iron ;  one- 
half  of  the  strap  is  forged  on  with  suitable  lugs,  and  the  other  half 
has  lugs  forged  on  for  bolting  the  hoop  together,  with  a  single  bolt 
and  nut  for  each  lug.  The  rubbing  surfaces  are  of  brass,  rivetted 
to  the  strap,  and  then  accurately  turned  to  suit  the  sheave.  The 
lugs  on  the  strap  do  not  fit  closely  together,  so  as  to  adjust  at  any 
time  the  rubbing  surface.  Suitable  mechanism  for  lifting  the 
eccentric  out  of  gear  when  starting  the  engine  should  be  arranged. 
This  may  be  worked  in  a  variety  of  ways;  with  hand  levers,  or 
with  a  foot  lever  and  rod  attachment,  which  the  attendant  can  press 


256 


MODERN    STEAM   PRACTICE. 


on  with  his  foot  while  his  hands  are  free  to  move  the  steam  regu- 
lating valve  and  hand  lever,  which  is 
placed  in  a  socket  on  the  gab  lever 
secured  to  the  weigh  shaft.  This  valve 
gear  and  mechanism  for  working  it  is 
very  simple,  and  suits  admirably  for 
engines  fitted  with  a  crank  shaft  and 
fly  wheel. 

The  cylinder  for  the  air  consists  of 
■3,  round  barrel  with  flanges  at  the 
ends,  truly  bored  out  and  the  flanges 
faced;  it  is  bolted  down  on  a  square 
base,  which  has  nine  openings  for  ad- 
mitting the  air  into  the  cylinder,  and 
one  large  opening  for  its  exit.     The 


!© 
■  ^  i 

:0/? 

c 

'               ©: 
\  B     B     B      ; 

\ _.©: 

^^^^^^^~ 


"^i^Vi 


Fig.  159. — Bottom  of  Blowing  Cylinder. 

A,  Bottom.   BB,  Valve  openings.  c,Discharge  former  opcuiugs  are  fitted  with  flap 

valves,  made  of  an  elastic  material, 

and  backed  with  suitable  wrought-iron  plates;  while  the  non-return 

valves  for  the  bottom  are  fitted  on 
the  passages  for  taking  away  the  air 
under  pressure.  The  base  is  securely 
bolted  down  with  one  large  bolt  at 
each  corner,  passing  through  holes 
left  in  the  foundation  to  the  girder 
plates  at  the  bottom,  and  the  bolts 
are  secured  with  keys  bearing  on 
these  plates;  thus  the  foundation  is 
firmly  bound  together  with  plates  at 
the  top  and  bottom  similar  to  the 
steam-cylinder  end. 

The  cover  for  the  cylinder  is  fitted 
with  a  packing  box  and  gland  for 
the  piston  rod,  and  has  three  open- 
ings for  the  admission  of  the  air,  and 
five  smaller  openings  placed  inside 
of  the  branch  cast  on  the  cover  for 
the  exit  of  the  air.  The  former  are 
fitted  with  valve  boxes,  which  are 
bolted  down  on  the  cover,  and  have 

a  door  fitted  to  the  top  of  each  box.     There  are  four  openings 


Fig.  160. — Cover  and  Valve  Boxes  for  Blowing 

Cylinder. 
A,  Cover.     B  B,  Valve  openings,     c,  Valve  chest, 
D  D,  Discharge  valve  openings. 


STATIONARY   ENGINES. 


2S7 


in  each,  and  the  valves  are  arranged  nearly  in  a  vertical  position, 
hinging  from  the  top;  while  the  valves  for  the  exit  of  the  air  are 


Fig.  i6i. — Top  Chest  for  Blowing  Cylinder. 
A,  Top  chest.     B,  Passage  on  the  cyUnder  cover. 


Fig.  162. — Bottom  Chest  for  Blowing  Cylinder. 
A,  Passage  for  cylinder.     B,  Bottom  chest. 


placed  quite  flat  on  the  cover,  and  are  secured — as  all  these  valves 
are — with  bolts  and  nuts,  having  a  narrow  strip  of  plate  for  the  nuts 
to  bear  on  at  the  hinge. 

The  top  and  bottom  chests  for  taking  away 
the  air  are  formed  of  separate  plates  bolted 
together  like  a  tank,  and  the  joints  rusted  with 
a  cement  made  of  fine  cast-iron  borings,  sal 
ammoniac,  and  sulphur.  The  proportions  used 
for  this  cement  are — sal  ammoniac,  2  parts; 
flower  of  sulphur,  i  part;  cast-iron  borings, 
200  parts.  It  requires  some  time  to  set,  and 
makes  a  first-rate  joint.  The  top  chest  is 
bolted  to  the  flange  cast  on  the  branch,  and 
the  bottom  one  is  let  into  the  socket  cast  on 
the  base  plate  and  then  rusted  up,  and  is  fitted 
with  an  inclined  plate  between  the  socket  and 
the  bottom  discharge  chest — this  plate  having 
four  openings  for  the  non-return  valves.  The 
top  and  bottom  chests  are  connected  by  means 
of  a  circular  column,  securely  bolted  at  the  top  Fig.  163.- Distance  Pipe  for  Air 

Chests  for  Blowing  Cyhnder. 

and  properly  joint-ed,  no  expansion  joint  being  ^, distance  pipe.  B.Loosenng. 

required.     The  pipe  for  leading  the  air  to  the 

wrought -iron  receiver  is  fitted  to  the  bottom  chest,  the   line  of 

piping  being  circular. 

17 


258 


MODERN   STEAM   PRACTICE. 


The  piston  for  the  blowing  cyhnder  should  be  light,  yet  strong. 
It  is  fitted  with  a  narrow  junk  ring  for  pressing  down  the  packing, 

and  held  down  with  bolts  and 
nuts  let  into  the  piston.  The 
piston  rod  has  a  cone  fitting  into 
a  corresponding  cone  in  the  pis- 
ton, and  is  secured  with  a  plain 
cotter  passing  through  the  boss 
of  the  piston  and  rod. 

We  will  now  consider  the  de- 
tails for  actuating  the  pistons  of 
the  steam  and  air  cylinders  simul- 
taneously. The  main  beam  is 
cast  in  two  halves,  and  held  together  by  cast-iron  distance  pieces 
with  flanges  for  bolting  to  the  halves.  All  the  holes  for  the  main 
gudgeons  should  be  accurately  bored  out,  and  the  gudgeons  turned 
to  fit.  The  one  for  the  main  connecting  rod  has  collars  turned  on 
it,  and  should  be  placed  in  position  before  the  beams  are  bolted 


y>^-»^y:»y^^y^yj:»!^^y^Js:^'S; 


\\v\v\\\\vsm\\^\\\^^v^\\^v<\^^ 


Fig.  164. — Piston  for  Blowing  Cylinder. 
A,  Piston.     B,  Junk  ring,     c.  Packing  space. 


Fig.  163. — Main  Beam. 
A,  Beam,     b,  Steam  cylinder  end.     c,  Air  cylinder  end.     D,  Boss  for  connecting-rod  gudgeon. 

together ;  all  the  other  gudgeons,  excepting  those  for  the  feed  and 
cold  water  pump,  have  the  journals  on  the  outside  of  the  beam, 
and  can  be  put  in  at  any  time;  they  are  held  in  position  with 
keys.  Some  engineers  prefer  fitting  four  keys  on  the  main  gud- 
geons, the  hole  being  left  larger,  and  after  the  keys  are  fitted  lead 
is  run  in,  filling  up  the  space ;  but  this  does  not  make  such  good 
work  as  boring  out  the  hole  the  exact  size.  For  heavy  cast-iron 
beams  of  all  descriptions,  neat  wrought-iron  hoops  should  be  shrunk 
on  the  main  boss,  thereby  binding  the  part  that  takes  the  whole 
strain  that  is  transmitted  through  the  beam. 

The  pillow  blocks  are  of  the  usual  description,  fitted  with  brasses. 


STATIONARY   ENGINES. 


259 


which  are  secured  by  means  of  covers  and  bolts;  a  broad  base  is 
cast  on  the  pillow  block,  and  bolted  at  the  ends  to  the  spring  beam, 


Fig.  i56. — Pillow  Block  for  the  Gudgeon  of  the  Main  Beam. 
A,  Pillow  block.        B,  Boss  for  holding-down  bolt. 

while  the  large  central  bolt  passing  down  through  each  column  also 
passes  through  a  hole  in  the  spring  beam  and  base  of  the  pillow 
blocks,  the  nut  bearing  on  the  top  of  the  base  plate — thus  firmly- 
bolting  the  pillow  blocks,  spring  beam,  entablature,  and  columns 
together. 

The  spring  beam  is  a  light  frame  of  cast  iron  running  the  entire 
length  of  the  engine  house,  and  is  built  into  the  walls  at  the  end. 
The  part  inclosing  the  beam  is  formed  as  a  half  circle  at  the  ends, 
and  in  long  spring  beams  a  cross  beam  runs  across  the  engine 
house  at  each  end,  and  is  built  into  the  side  walls.  The  spring  beam 
proper  ends  at  this  cross  beam,  but  its  continuity  is  maintained  by 
bolting  girders  to  the  ends,  which  are  built  into  the  walls;  these 
and  the  cross  girders  are  placed  in  mainly  to  support  the  spring 
beam  and  carry  the  floor.  In  some  cases  stone  flags  are  laid  down, 
but  open  cast-iron  foot  plates  are  preferable,  and  when  neatly 
executed  give  a  light  and  airy  appearance  to  the  engine  room. 
When  the  engine  is  under  repair,  heavy  weights  must  not  of  course 
be  placed  on  such  a  floor.  Planking  should  be  laid  down  on  the 
top  of  the  beams  which  run  across  the  engine  room  for  carrying  the 
cast-iron  floor  plates ;  they  should  be  made  with  thin  raised  parts, 


26o 


MODERN    STEAM   PRACTICE. 


with  side  flange  pieces.     By  this  means  the  floor  plates  are  sup- 
ported, and  kept  sHghtly  apart  from  one  another  in  the  length  of 


2)  ^D  I> 

Fig.  167. — Spring  Beam. 
A,  Spring  beam,     b.  Cross  beam,     c  c.  Pillow-block  seats.     D  d.  Bosses  for  holding-down  bolts. 

the  building,  but  across  the  building  they  are  simply  placed  end 
to  end. 

The  entablature  placed  between  the  spring  beam  and  the  top  of 
the  columns  runs  across  the  building,  and  is  built  into  the  side  walls, 
and  securely  joggled  and  bolted  to  the  spring  beam.  It  is  best  to 
form  the  entablature  in  two  pieces,  which  are  placed  a  short  dis- 
tance apart,  and  are  hollowed  out  to  take  a  projection  cast  on  the 
top  of  each  column.  All  these  longitudinal  and  cross  beams  are 
supported  by  two  columns,  which  rest  on  cast-iron  plates  laid  on 


STATIONARY   ENGINES. 


261 


the  top  of  the  foundation ;  each  column  is  bolted  down  with  one 
central  bolt  passing  down  to  the  bottom  of  the  foundations,  and  a 
cross  plate  takes  both  of  the  bolts,  which  are  secured  at  the  ends 


^ 


:  A 


[V^~-" 


Fig.  168. — Pillars  and  Entablature. 
A,  Pillar.     B,  Recess  for  bolt  heads,     c.  Entablature.     D  d,  Hollows  for  pillars.     E,  Wall  bos. 

with  proper  keys,  like  all  the  main  holding- down  bolts  for  the 
cylinders  and  crank-shaft  arrangements. 

The  pillow  blocks  for  the  crank  shaft  are  fitted  with  thick  brasses 
and  strong  caps  and  bolts,  and  at  the  crank  end  a  plate  is  laid 
down,  butting  against  the  steam  cylinder  and  central  pedestals  of 
the  foundation.  This  plate  has  fitting  strips  cast  on  it  with  the 
necessary  joggles  for  fitting  and  securing  the  blocks  at  the  ends ; 
holes  are  also  cast  in  it  for  bolting  the  pillow  block  to,  and  for  the 


262  MODERN   STEAM   PRACTICE. 

holding-down  bolts  which  pass  down  through  the  foundation.     At 


Fig.  169. — Pillow  Block  for  Crank  Shaft. 
A,  Pillow  block.     B,  Bed  plate. 

the  other  end  of  the  crank  shaft  a  plate  is  let  into  the  side  wall,  a 
proper  arch  being  formed  in  the  wall  for  its  reception. 

The  crank  shaft  and  crank 
are  of  wrought  iron,  the  latter 
being  bored  in  the  main  eye, 
somewhat  smaller  than  the 
part  of  the  shaft  where  it  is 
shrunk  on.  The  crank  is 
slightly  heated  for  that  pur- 
pose, it  is  then  slipped  on  the 
shaft,  and  cold  water  poured 
over  it,  thus  shrinking  it 
tightly  on.  The  shaft  should 
be  only  a  very  little  more  in 
diameter  than  the  eye,  as 
when  too  much  is  allowed  it 
is  apt  to  strain  the  material 
and  weaken  the  eye.  The 
ig.  170.—  am  ran  crank  and  shaft  should  have 

A,  Crank,      b.  Crank  pin  rivetted  in.  . 

a   keyway  cut   prior  to  the 
operation  of  shrinking  on,  and  when  it  is  cleaned  out  quite  smooth 


STATIONARY   ENGINES, 


263 


and  fair  the  key  is  driven  tightly  in  with  a  few  strokes  of  a  sledge 
hammer,  and  then  cut  off  and  filed  quite  smooth  at  the  ends.  The 
crank  pin  is  held  firmly  in  its  eye  by  heating  the  eye  and  driving 
the  pin  in  with  a  hand  hammer,  and  then  pouring  water  over  it,  the 
eye  contracting  and  firmly  binding  the  pin,  which  is  then  rivetted 
over  at  the  end,  a  part  being  turned  out  in  the  pin  for  that  purpose. 

The  main  comiecting  rod  is  generally  of  wrought  iron,  turned 
from  end  to  end,  except 
the  square  parts  for  tak- 
ing the  straps,  which  are 
fitted  with  brasses,  having 
a  jib  and  key,  with  a  screw 
turned  on  the  key,  which 
passes  through  an  oblong 
hole  in  the  bent  part 
formed  on  the  jib,  the 
screw  being  fitted  with  a 
nut  on  each  side  of  the 
jib.  The  rod  is  finished 
bright  all  over,  or  at  least 
it  should  be  turned  all 
over  and  painted.  Some 
connecting  rods  for  the 
blowing  engine  are  made  of  oak,  with  wrought -iron  straps  on 
each  side,  well  bolted  and  hooped,  and  a  metal  piece  at  each  end 
securely  bolted  through  the  straps ;  this  piece  is  for  the  brasses  to 
abut  against.  The  latter  are  held  in  position  with  jibs  and  keys. 
Although  this  form  of  connecting  rod  has  not  such  a  handsome 
appearance  as  the  metal  one,  yet  it  answers  the  purpose  very  well. 
There  is  but  little  strain  on  it,  as  it  merely  (in  connection  with  the 
crank)  changes  the  reciprocating  motion  of  the  pistons, — in  fact,  it 
should  just  be  made  stiff  enough  to  resist  the  strain  at  the  dead 
centre,  as  it  is  termed,  elsewhere  it  merely  imparts  motion  to  the 
fly-wheel  shaft.  It  must  be  borne  in  mind,  however,  that  a  wrought- 
iron  connecting  rod  balances  the  heavy  piston  of  the  air  cylinder 
much  better  than  one  made  of  lighter  material. 

For  convenience  of  transportation  the  fly  wheel  is  built  up  in 
segments.  Its  central  part  is  cast  in  one  piece,  and  suited  for  eight 
arms,  each  arm  having  its  segment  cast  along  with  it.  These  seg- 
ments are  dovetailed  into  one  another  at  the  joinings,  and  then 


Fig.  171. — Connecting  Rod. 

A,  Body  of  rod.     b.  Butt,     c,  Jib  and  cotter. 
E,  Strap. 


D,  Brasses. 


264 


MODERN   STEAM   PRACTICE. 


firmly  secured  with  oak  and  thin  iron  wedges;  the  same  mode  of 
fastening  the  arms  into  the  central  part  being  adopted.     Of  course 


Fig.  172.— Fly  Wheel. 
A,  Boss.     B,  Wedging  space  for  arm.     c,  Arm.     D,  Rim.     E,  Dovetail  at  end. 

there  are  other  ways  of  fastening  with  bolts  and  nuts,  used  for  fly 
wheels  for  general  purposes.  The  boss  is  keyed  on  the  shaft  with 
a  number  of  keys ;  but  it  is  preferable  to  bore  out  the  eye  the  same 
diameter  at  the  raised  part  of  the  shaft,  where  it  is  fitted  on  with 
four  keys,  and  a  wrought-iron  hoop  should  be  shrunk  on  each  side 
of  the  boss ;  by  this  means  the  keys  can  be  firmly  driven  home 
without  danger  of  splitting  the  boss,  although  there  is  not  much 
risk  of  this  when  the  metal  is  properly  proportioned  and  care  is 
taken  to  fit  the  keys;  they  should  in  the  first  instance  be  driven 
with  a  hand  hammer  until  nearly  home,  with  the  surface  bearing 
all  over  and  filed  quite  smooth,  then  a  few  blows  witli  a  large 
hammer  are  given  to  complete  the  operation. 


STATIONARY   ENGINES.  265 

The  piston  rods  of  both  cylinders  are  connected  to  the  beam  by 


Fig.  173. — Crosshead. 
A,  Cast-iron  crosshead.     b,  Gudgeon,     c.  Collars,     d,  Piston  rod.     e.  Jib  and  cotter. 

cast-iron  crossheads  and  wrought- iron  side  links,  and  the  vertical 

2 


Fig.  174. — Main  and  Back  Links  for  Parallel  Motion. 

A,  Main  link.      b.  Distance  pillar.       c.  Jibs  and  cotter.      d  d.  Plates.      E,  Back  link. 

F,  Cotter  for  brasses. 


266 


MODERN   STEAM   PRACTICE. 


line  is  attained  with  the  ordinary  parallel  motion,  having  fore  and 
back  links,  parallel  bars,  radius  rods,  and  cross  gudgeons  for  the 
back  links.  The  cast-iron  crossheads  are  turned  all  over,  and  are 
secured  to  the  piston  rods  with  jibs  and  cotters;  on  each  side  a 
cast-iron  ring  and  thin  brass  collar  is  laid  on  the  gudgeon,  which 
is  secured  with  a  key  at  each  end ;  the  outside  bearings  are  for 
the  main  links,  while  the  large  eye  of  the  parallel  bar  is  placed 
between  the  main  links  and  the  brass  washers. 

The  main  links  (Fig.  174)  are  plain  wrought-iron  straps,  fitted  with 
brasses  at  the  top  and  bottom,  having  a  distance  column  between 
them,  bearing  on  wrought-iron  plates  fitted  between  the  flanges  of 
the  brasses  at  the  bottom  of  the  top  pair  and  at  the  top  of  the  bottom 
pair;  these  brasses  are  held  in  position  with  two  jibs  and  one  key,  a 
screw  bolt  being  formed  on  the  bottom  jib,  fitted  with  two  nuts,  one 
on  each  side  of  the  eye  formed  on  the  end  of  the  key,  an  elongated 
hole  being  made  in  the  eye.  The  straps  in  some  cases  are  turned 
all  over  on  the  outside,  and  oil  cups  formed  on  their  tops;  when  got 


A 

** 

^ 

■ — 


Fig.  175.— Bull's  Eye  and  Cross  Shafts  for  Parallel  Motion. 
A,  Cross  shaft  for  cold-water  pump  rod.     B,  Bull's  eye  for  cold-water  pump  rod.     C,  Cross  shaft. 

up  in  first-class  style  they  add  greatly  to  the  beauty  of  the  engine. 
The  back  links  are  two  plain  round  rods ;  the  one  for  the  steam 
cylinder  has  eyes  forged  on  the  ends,  fitted  with  brasses  held  by  a 
single  key,  and  the  one  for  the  air-cylinder  end  has  an  eye  at  the 
middle  for  taking  a  bent  cross  bar,  to  which  the  cold-water  pump 
rod  is  secured.  The  bottom  bar  has  an  elongated  eye  at  the  middle 
for  the  rod  to  pass  through,  the  cross  bar  for  the  back  link  of  the 


STATIONARY   ENGINES. 


267 


n 


U 


7 


& 


^ 


Fig.  176. — Bracket  for  Parallel  Motion. 
A,  Bracket.     B,  Pin  secured  with  nut 


steam-cylinder  end  being  quite  plain.  The  parallel  bars  are  fitted 
to  the  crosshead  and  to  the  cross  bars  on  the  back  links,  the  brasses 
being  adjusted  with  a  single  key; 
the  radius  rods  are  similar,  and 
work  on  a  pin  fitted  to  a  bracket 
which  is  secured  to  the  spring 
beam  at  the  cylinder  end,  and 
the  other  eye  takes  the  cross  bar 
for  the  back  links.  In  setting  out 
this  parallel  motion,  the  length 
of  the  links  from  centre  to  centre 
is  one-half  of  the  piston  stroke; 
the  centre  for  the  back  links  on  the  beam  is  equidistant  from  the 
end  of  the  beam  and  the  centre  of  vibration.  The  parallel  and 
radius  rods  are  exactly  this  length 
from  centre  to  centre,  or  the  dis- 
tance from  the  back-link  centre  to 
the  end  centre  of  the  beam ;  the 
true  line  of  the  piston  rods  being 
one-half  of  the  versed  sine  of  the 
chord  contained  by  the  full  arc 
delineated  by  the  travel  of  the 
beam,  taking  the  distance  from  the 
end  centre  to  the  centre  of  vibra- 
tion as  the  radius. 

The  cold-water  pump  is  a  plain 
open  barrel,  fitted  with  a  suction 
valve  of  leather,  stiffened  with 
wrought -iron  plates  at  the  top 
and  bottom,  rivetted  through  and 
through,  and  hinged  on  a  separate 
conical  valve  seat.  A  cross  bar, 
having  an  eye  at  the  top,  is  fitted 
for  holding  down  the  leather,  and 
for  drawing  out  the  valve  and 
seating;  this  is  secured  to  the 
latter  by  a  cotter  passing  through 
the  shank  forged  on  the  cross  bar, 
the  cotter  bearing  on  the  under  side  of  the  web  cast  along  with 
the  seating.     The  bucket  is  fitted  with  a  valve  of  a  similar  descrip- 


A 


A 


B 


(J 


Fig.  177. — Parallel  and  Radius  Rods  for  Parallel 
Motion.  —  A,  Parallel  rod.    b,  Radius  rod. 


268 


MODERN    STEAM   PRACTICE. 


tion.  The  packing  of  the  bucket  is  a  plaited  gasket,  or  gutta- 
percha rings  may  be  adopted,  and  kept  to  the  circumferential  sur- 
face of  the  barrel  by  the  hydraulic  pressure  of  the  water,  a  small 
hole  being  bored  at  the  top  in  communication  with  the  recesses 
left  in  the  bucket.  The  pump  rod  is  connected  to  the  cross  shaft 
placed  at  the  centre  length  of  the  back  link,  passing  through  an  eye 
formed  on  the  shaft  at  the  bottom  end.  The  water  is  pumped  into 
a  cistern  provided  with  an  overflow  pipe,  the  exhaust  steam  passing 
over  the  surface  of  the  water  and  then  escaping  through  another  pipe 

into  the  atmosphere;  by  this  means 
the  feed  water  is  heated  before  it  is 
forced  into  the  boiler  by  a  plunger 
pump,  the  rod  for  working  it  being 
connected  directly  to  the  beam  by  a 
gudgeon  passing  through  it,  and  to  the 
plunger  with  a  pin  joint.  The  valves 
and  their  seatings  are  of  brass ;  and 
a  relief  valve  should  be  fitted,  loaded 
with  a  weight,  to  return  the  water 
into  the  well  or  pond  from  which  it  is 
drawn  by  the  cold-water  pump.  This 
of  course  is  only  required  when  a  re- 
gulating valve  is  placed  on  the  boiler; 
but  should  the  valve  for  regulating 
the  supply  to  the  feed  pump  be  placed 
on  the  suction  pipe,  a  relief  valve  may 
be  dispensed  with.  In  either  case, 
however,  it  is  desirable  to  have  one 
fitted  close  to  the  pump,  so  that  in  the 
event  of  the  water  in  the  feed  pipes 
freezing  the  line  of  piping  may  not 
be  damaged;  and  to  guard  against  this  evil,  a  small  plug  tap 
should  be  fitted  to  the  line  of  feed  pipes,  and  so  placed  that  all  the 
water  may  be  run  off  between  the  check  valve  on  the  boiler  and 
the  pump. 

The  steam-regulating  valve  fitted  to  the  nozzle  chest  should  be 
placed  so  that  the  attendant  can  reach  it  easily  when  starting  the 
engine.  It  consists  of  a  sluice  valve  of  brass,  fitted  on  a  cast-iron 
face,  accurately  planed  and  scraped  to  a  true  surface, — the  valve 
chest  being  fitted  with  two  covers  to  facilitate  the  operation  of 


Fig.  178.— Feed  Pump. 

A,  Pump.      B,  Plunger.      c.  Suction  valve. 

D,  Delivery  valve.     E  E,  Brackets. 


STATIONARY   ENGINES. 


269 


-^^ 


iiii 


A,  Valve  chest.     B,  Valve. 
C,  Handle. 


scraping  truly.     One  of  these  covers  is  fitted  vi^ith  a  packing  gland 

for  the  valve  rod,  which  is  actuated  with  a  lever  handle  having  a 

stud   fitted  to  the 

valve  box,  with  a 

joint   and   pin  for 

taking  the  starting 

handle.    The  valve 

rod    is  secured   to 

the   valve   with   a 

pin  passing  through  two  snugs  cast  on  the 

valve,  and  has  a  slot  orosshead  keyed  on  the 

outside,  which  the  handle  passes  through. 

The  arrangement  of  the  boilers  for  this 
engine  is  described  in  the  section  treating  on 
boilers  (p.  39).  Three  egg-ended  boilers 
were  supplied,  each  38  feet  in  length  and 
5  feet  7  inches  in  diameter.  ^^^^^^ 

In  some  examples  of  blowing  engines  erec-  Fig.  179.— steam-reguiadngVaive. 
ted  at  the  Dowlais  Iron  Works  the  general 
arrangements  are  the  same  as  the  foregoing. 
The  beam  is  supported  on  a  wall  carried  up  from  the  foundation, 
with  a  cast-iron  wall  box  on  which  the  pillow  blocks  are  fitted. 
This  pedestal  is  secured  by  long  bolts  and  nuts  passing  through  a 
plate  at  the  bottom  of  the  foundation ;  these  bolts,  passing  from  the 
top  to  the  bottom,  firmly  bind  together  the  lever  wall.  The  pillow 
blocks  are  securely  bolted  and  joggled  to  the  wall  box,  and  are  fitted 
with  brasses,  but  there  are  no  caps,  the  brasses  being  held  down 
with  jibs  and  cotters  passing  through  the  sides  of  the  pillow-block 
frame.  Wooden  spring  beams  are  substituted  instead  of  cast  iron ; 
they  are  let  into  the  box  on  the  lever  wall,  and  pass  along  to  the 
end  walls  of  the  engine  house;  transverse  beams  also  are  secured 
to  the  longitudinal  ones  for  supporting  the  flooring.  The  beam  is 
fitted  with  parallel  motion,  the  main  links  taking  the  cros&head  of 
the  piston  rods  being  placed  between  the  beams,  as  are  also  the 
back  links.  The  parallel  bars  and  radius  rods  are  fitted  outside 
of  these,  the  latter  taking  a  pin  on  a  cast-iron  bracket  bolted  to 
the  spring  beam. 

The  steam  cylinder  in  this  example  (Figs.  180,  181)  is  55  inches 
diameter,  stroke  of  piston  13  ft;  number  of  strokes  per  minute,  20; 
steam  pressure,  60  lbs.  per  square  inch.     An  ordinary  slide  valve 


270 


MODERN   STEAM   PRACTICE. 


worked  by  an  eccentric  is  fitted,  having  a  gridiron  expansion  valve, 
working  on  the  back  of  the  valve  casing,  arranged  to  cut  off  the  steam 


<-         4) 


no 

>     - 
a   ^ 
.2 
c  <S 

>;   ">   rt 

W  ^   to 

,  c    u 

a 


CIS      . 

"  e  . 

ii    <«    B 


"I 

c    S 


(55  c  _ 


2-3 


4)    |.-^ 


^.S 


n-S 


•3  S 

M 


at  one-third  of  the  stroke  of  the  piston.     Both  of  the  valve  chests 
are  formed  in  one  casting,  each  having  a  separate  cover;  they  are 


STATIONARY   ENGINES. 


271 


placed  at  the  bottom  of  the  cyHnder,  with  a  connecting  pipe  fitted  with 
an  expansion  joint,  forming  the  passage  to  the  top  of  the  cyhnder. 
A  separate  sHde  valve  is  also  fitted  for  starting  the  engine,  which  is 


^^m^N^^^^^M-^^ 


Fig.  181. — Blowing  Engine  at  the  Dowlais  Iron  Works.  End  Elevation. 

worked  by  hand ;  but  the  main  slide  valve  has  the  ordinary  eccentric 
motion,  with  weigh  shaft  side  rods  and  crosshead  overhead,  the 
valve  rod  being  guided  at  the  top  by  a  stud  placed  on  the  passage 
between  the  top  and  bottom  of  the  cylinder.     The  valve  rod  passes 


2^2 


MODERN   STEAM   PRACTICE. 


through  a  stuffing  box  on  the  under 
•  side  of  the  valve  casing.  The 
expansion  valve  rod  also  passes 
through  stuffing  boxes  at  the  top 
and  bottom,  and  may  be  actuated 
by  an  eccentric  or  cam  motion. 
The  pedestal  for  bolting  the  cylin- 
der to  rests  on  massive  frames  of 
cast  iron,  and  is  raised  somewhat 
above  the  line  of  the  crank  shaft; 
the  castings  under  the  cylinder 
weigh  75  tons,  and  the  foundations 
contain  10,000  cubic  feet  of  lime- 
stone in  large  blocks ;  thus  securing 
a  firm  bedding  for  the  machinery. 
When  the  main  parts  of  such  heavy 
castings  can  be  run  from  smelting 
furnaces  where  the  engine  is  to  be 
fitted  up,  of  course  cast  iron  is 
.largely  used;  but  where  transport 
is  necessary  recourse  must  be  had 
to  the  usual  mode  of  building  the 
foundations  with  stone  or  brick- 
work laid  in  cement. 

The  crank  is  of  cast  iron,  but  the 
shaft  is  better  of  wrought  iron,  al- 
though many  cast-iron  ones  are 
in  use.  The  pillow  block  for  the 
crank  end  rests  on  one  of  the 
frames  to  which  the  cylinder  pe- 
destal is  bolted ;  the  other  end  of 
/  the  shaft  passes  through  the  side  of 
the  engine  house,  and  is  supported 
by  a  pillow  block  resting  on  a  mas- 
sive wall  plate. 

The  fly  wheel  is  22  feet  in  dia- 
meter, weighs  about  35  tons,  and 
\  is  fitted  up  in  segments  in  the  usual 
manner,  the  arms  being  fitted  into 


fig.  1S2. — Section  through  Steam  Valves. 
D,  Slide  valve,     e.  Expansion  valve,     f,  Small  valve  for  moving  the  engine. 


STATIONARY   ENGINES.  2/3 

a  large  centre  piece,  and  securely  dovetailed  into  the  rim  at  the 
extreme  diameter. 

The  main  part  of  the  connecting  rod  is  of  oak,  strapped  with 
wrought  iron  from  end  to  end,  well  bolted  together,  and  in  addition 
secured  with  a  strong  hoop  shrunk  on  at  the  middle.  Blocks  of  cast 
iron  are  fitted  to  the  ends  of  the  rod  for  the  brasses  to  bear  against, 
the  blocks  being  bolted  through  and  through  the  straps;  and  as  both 
ends  of  the  rod  are  forked,  the  brasses  are  adjusted  with  deep  jibs 
and  keys.  The  top  end  is  placed  between  the  beam,  as  in  the 
previous  example. 

The  beam  has  a  total  length  of  40  feet  between  the  outside 
centres,  and  is  so  arranged  as  to  give  a  stroke  of  1 3  feet  to  the 
steam  piston  and  12  feet  to  the  air  piston.  It  is  cast  in  halves,  each 
half  weighing  16^  tons,  the  total  weight  on  the  centre  gudgeon, 
including  all  the  minor  details,  being  about  44  tons.  The  wall  for 
supporting  the  beam  and  its  adjuncts  is  7  feet  in  thickness,  built  of 
stone  accurately  dressed;  the  pedestal  on  which  the  main  pillow 
blocks  rest  is  bolted  down  with  twelve  bolts,  3  inches  in  diameter, 
taking  a  wall  plate,  the  extreme  breadth  of  the  lever  wall,  placed 
below  the  level  of  the  floor,  for  the  blowing-cylinder  end. 

The  blowing- cylinder  is  144  inches  in  diameter,  stroke  12  feet;  and 
as  the  piston  makes  twenty  double  strokes  per  minute,  the  quantity 
of  air  discharged  is  nearly  54,283  cubic  feet  per  minute,  delivered  at 
a  pressure  of  33^  lbs.  per  square  inch.  The  area  of  the  e'ntrance 
valves  is  56  square  feet,  and  that  of  the  delivery  valves  16  square 
feet.  The  cylinder  is  cast  in  two  pieces,  and  is  bolted  down  to  the 
bottom  plate,  which  is  strongly  ribbed  in  the  casting,  and  arranged 
with  a  suitable  number  of  openings  for  the  air  flap  valves.  This 
bottom  plate  is  supported  on  pillars  of  cast,  iron  at  convenient 
distances  all  round,  which  are  stepped  on  a  massive  cast-iron  plate 
resting  on  the  top  of  the  foundation,  and  to  which  it  is  bolted  with 
long  bolts  passing  down  through  the  foundations,  and  secured  at 
the  bottom  with  keys  bearing  on  a  wall  plate  built  into  the  stone- 
work. The  cover  is  fitted  with  valve  boxes,  as  in  the  previous 
example,  the  flap  valves  beating  against  the  angular  sides  of  the 
boxes.  The  boxes  are  fitted  with  covers  at  the  top,  through  which 
the  inside  of  the  cylinder  may  be  inspected.  There  are  also  fitted 
at  the  top  and  bottom  large  entrance  valves,  placed  vertically 
immediately  over  and  under  the  discharge  passages.  The  non- 
return or  discharge  valves  are  placed  in  a  line  with  and  immediately 

18 


274 


MODERN   STEAM   PRACTICE. 


opposite  the  large  entrance  valves,  and  are  fitted  to  the  discharge 
chambers.  The  discharge  pipe  is  5  feet  in  diameter,  it  is  carried 
140  yards  in  length,  and  acts  as  a  capital  regulator,  providing  a 


Fig.  183. — Vertical  Section  of  Blowing  Cylinder. 

A,  Cylinder,    b  b,  Bottom  valves,    c  c,  Top  valves.    D,  Top  discharge  valves.    E,  Bottom  discharge  valves. 
F,  Discharge  pipe.     G,  Pillars  for  supporting  the  bottom  plate  of  the  cylinder. 

uniform  blast  to  the  furnaces,  the  engine  being  calculated  for  sup- 
plying a  blast  to  eight  furnaces,  whose  diameters  across  the  boshes 
vary  from  16  to  18  feet. 

Eight  boilers  are  supplied,  of  the  Cornish  description,  each  42  feet 
long  and  7  feet  in  diameter,  with  a  single  flue,  4  feet  in  diameter, 
running  from  end  to  end.  The  length  of  fire  grate  is  9  feet — which 
is  too  long  to  manage  properly. 


SIDE -LEVER   COMBINED  BLOWING  ENGINES. 

High  and  low  pressure  combined  engines  have  been  successfully 
adopted  for  blowing  furnaces.  The  side  levers,  two  in  number,  are 
placed  one  on  each  side  of  the  steam  cylinders;  the  high -pressure 


STATIONARY   ENGINES. 


275 


cylinder  being  at  one  end,  and  the  low-pressure  cylinder  at  the 
other  end.  The  blowing  cylinders  are  placed  overhead,  and  rest 
on  stone  pedestals  built  up  from  the  foundation.    The  engine  house 


Fig.  184.— Side-lever  Combined  Blowing  Engines,  by  Wilson  of  Patricroft. 

is  about  75  feet  long,  60  feet  wide,  and  72  feet  in  height,  and  con- 
tains three  pairs  of  engines. 

The  high-pressure  cylinder  is  45  inches,  and  the  low-pressure  one 
66  inches  in  diameter;  the  blowing  cylinders  are  each  100  inches 
in  diameter;  and  the  length  of  stroke  for  all  the  pistons  is  12  feet 


2/6  MODERN    STEAM   PRACTICE. 

Cornish  valve  gear,  arranged  for  double  action,  is  fitted  to  both  of 
the  steam  cylinders.  The  steam,  after  doing  duty  on  the  top  of 
the  high-pressure  piston,  expands  on  the  top  of  the  low-pressure 
piston  (and  vice  versa),  and  then  exhausts  into  the  condenser;  it 
will  therefore  be  understood  that  two  steam  valves  and  two  exhaust 
valves  are  fitted  to  each  cylinder.  The  hand  gear  is  placed  on  the 
low-pressure  cylinder,  and  is  connected  by  rods  running  below  the 
flooring  to  the  gear  for  the  high-pressure  cylinder;  the  attendant, 
therefore,  from  one  platform  can  actuate  by  hand  all  the  eight  valves; 
or,  in  other  words,  the  movement  of  the  one  set  of  gear  for  the 
steam  valves  of  the  one  cylinder  controls  the  movement  of  the 
steam  valves  of  the  other  cylinder — the  exhaust  valves  acting  in  the 
same  way.  Thus  it  will  be  seen  that,  with  a  steam  and  exhaust 
valve  fitted  at  the  top  and  bottom  of  each  cylinder,  the  action  will  be 
as  follows:  Supposing  steam  from  the  boiler  is  acting  on  the  bottom 
of  the  high -pressure  cylinder,  forcing  up  the  piston,  the  lower 
exhaust  valve  and  top  steam  valve  are  shut  and  the  top  exhaust 
valve  open,  while  the  top  steam  valve  on  the  low-pressure  cylinder 
is  open  and  the  top  exhaust  shut;  thus  the  steam  expands  from 
the  top  of  the  small  cylinder  into  the  large  one,  at  the  same  time 
the  exhaust  valve  for  the  under  side  of  the  low-pressure  cylinder  is 
open  to  the  condenser,  the  bottom  steam  valve  being  shut.  The 
reverse  of  this  takes  place  on  the  downward  motion  of  the  high- 
pressure  piston.  Thus  the  high -pressure  piston  is  raised  and 
depressed  by  steam  direct  from  the  boiler,  while  the  low-pressure 
piston  is  raised  and  depressed  by  the  exhaust  steam  from  the  high- 
pressure  cylinder.  An  additional  benefit  accrues  from  the  final 
condensation  of  the  steam,  as  the  top  and  bottom  of  the  cylinder 
are  in  alternate  communication  with  the  condenser;  power  is  thus 
gained  and  fuel  economized.  The  arrangement  of  the  Cornish 
valve  gear  may  appear  complicated  when  applied  to  one  engine; 
but  it  must  be  remembered  that  this  complexity  consists  merely 
in  an  increase  of  parts,  as  the  whole  of  the  gearing  is  joined  together 
and  works  in  unison. 

The  main  side  levers  have  a  length  of  about  38  feet  from  centre  to 
centre,  and  each  weighs  upwards  of  20  tons;  they  are  connected  to 
the  crosshead  of  the  piston  rod,  common  to  both  cylinders,  by  side 
rods.  The  vertical  motion  of  the  piston  rods  and  crosshead  is  main- 
tained by  cast-iron  guides,  the  distance  from  the  top  of  the  steam 
cylinders  to  the  bottom  of  the  blowing  cylinders  being  about  17  feet. 


STATIONARY   ENGINES. 


2^^ 


The  air  pump  is  worked  by  means  of  a  crosshead  with  connecting 
rods  from  the  side  levers ;  the 
plug  rod  for  the  valve  me- 
chanism is  a  continuation  of 
the  air  pump  rod,  guided  at 
the  top  with  a  bracket  fitted  to 
the  nozzle  chest.  It  is  essen- 
tial for  this  class  of  engine  to 
have  a  travelling  crane  fitted 
overhead,  so  as  to  lift  the  pis- 
tons, &c.,  for  inspection  or 
repair. 

VERTICAL   BLOWING   ENGINES. 


Another  example  is  the 
vertical  direct -acting  high- 
pressure  engine,  which  differs 
materially  from  the  foregoing 
in  having  no  side  levers  or 
beams.  The  blowing  cylin- 
ders are  placed  on  the  ground 
floor,  four  strong  cast-iron 
pillars  are  securely  fitted,  one 
at  each  corner,  and  carried  up 
to  the  top  of  the  house,  with  J  I 
cross  girders  for  carrying  the 
steam  cylinder  and  fly-wheel 
shaft.  The  blowing  cylinder 
is  io8^  inches  in  diameter, 
and  the  steam  cylinder,  placed 
overhead,  is  47/^  inches  in 
diameter;  the  stroke  of  each 
is  6  feet  6^  inches.  The  fly- 
wheel shaft  is  25  feet  10  inches 
above  the  floor  of  the  engine, 

and  the  total    height    from  the     Fig.  iSs.-Vertical  Blowing  Engine  at  the  Creuzot  iron 

'-•  Works,  dep.  Saone-et- Loire,  r  ranee. 

base  to  the  centre  of  the  crank  a.  Blowing  cylinder,     b,  steam  cylinder,     c.  Crank  shaft 
shaft  is  about  44  feet   3   inches.       ^'flywheel,     e,  Bottom  of  air  cylinder,     kp.  Pillars. 

The  crank  is  connected  by  a  rod  to  a  crosshead  working  in  guides, 


278 


MODERN   STEAM    PRACTICE. 


taking  the  rod  for  the  steam  piston,  which  passes  down  through 
a  stuffing  box  at  the  bottom  of  the  steam  cyHnder,  and  is  con- 
nected to  the  piston  for  the  blowing  cyhnder.  This  class  of 
blowing  engine  has  a  fly  wheel ;  the  valve  gearing  is  worked  from 
the  fly  wheel  shaft,  spur  wheels  being  used  to  drive  a  cam  shaft 
which  actuates  equilibrium  valves.  The  steam  is  admitted  into  the 
cylinder  at  a  pressure  of  60  lbs.  per  square  inch,  and  is  cut  off  at 


Fig.  186. — Table  Blowing  Engine. 

A,  Blowing  cylinder.  b,  Steam  cylinder.  c,  Crank  shaft.  DD,  Fly  wheels. 
F  F,  Eccentrics  for  air  valve.  G,  Eccentric  for  steam  valve.  h.  Steam  valve. 
K,  Crosshead.     l,  Guides.     M  M,  Air  pipes. 


E,  Air  valve. 
1 1,  Side  rods. 


about  one-fourth  of  the  stroke;  the  number  of  revolutions  of  the 
crank  shaft  is  about  fifteen.  The  inlet  and  exit  valves  for  the 
blowing  cylinder  are  arranged  on  the  cover  and  bottom  of  the 
cylinder;  small  flap  valves  are  used,  one-half  of  the  area  being  for 
the  inlet,  and  the  other  half  for  the  exit  of  the  air,  which  is 
delivered  at  a  pressure  of  about  3  lbs.  per  square  inch,  and  the 
quantity  is  about  90  per  cent  of  the  cubical  contents  of  the  cylinder 
at  each  stroke. 


STATIONARY   ENGINES.  279 

Vertical  Table  Engine. — We  shall  now  notice  the  kind  of  blowing 
engines  called  "self-contained,"  that  is,  those  erected  on  one  bed  plate 
carrying  the  whole  of  the  engine.  Of  this  class  are  the  vertical  table 
engines,  which  are  constructed  for  easy  transport,  all  the  parts  being 
as  light  as  possible  (Fig.  186).  The  blowing  cylinder  stands  on  a 
pedestal  bolted  to  the  bed  plate.  The  diameter  of  the  cylinder  is  30 
inches;  stroke  of  piston  2  feet  6  inches,  making  80  strokes  per  minute. 
These  engines  being  small,  a  greater  number  of  them  must  of  course 
be  provided ;  and  when  large  sizes  are  adopted  the  weight  of  the 
various  parts  becomes  a  serious  matter.  The  piston  of  the  blowing 
cylinder  is  packed  with  hemp,  with  a  junk  ring  to  press  it 
down.  The  openings  for  admitting  the  air  into  the  cylinder 
are  formed  on  the  circumference  at  the  top  and  bottom;  a 
projecting  flange  is  cast  on  at  the  top  and  bottom,  the  bars 
between  the  opening  being  inclined,  similar  to  the  piston-  =^ 
valve  arrangement  already  described.  The  valve  is  of  the 
annular  description,  encircling  the  whole  cylinder  from  top  pj^  ^g^ , 
to  bottom ;  the  rubbing  surfaces  are  formed  of  brass  rings 
accurately  bored  out.  The  body  of  the  valve  is  formed  of  thin 
wrought-iron  plates,  securely  fastened  with  a  number  of  small  bolts 
to  two  cast-iron  rings,  which  are  bored  out  inside  for  the  reception 
of  the  brass  packing  rings.  These  rings  fit  the  recesses  in  the 
cast  iron  and  face  on  the  cylinder  without  any  other  packing;  and 
as  they  are  cut  through  the  wear  can  be  adjusted  with  a  thin  slip 
of  metal  or  paper,  and  then  properly  secured  with  bolts,  although 
there  is  but  little  wear  with  this  description  of  valve,  owing  to  its 
being  perfectly  balanced.  The  air  from  both  ends  of  the  cylinder 
passes  into  the  annular  space  between  the  cylinder  and  the  valve, 
from  which  it  escapes  by  two  pipes,  placed  opposite  each  other, 
with  flanges  for  jointing  them  to  the  cylindrical  part  of  the  valve. 
The  pipes  at  the  other  end  slide  on  a  vertical  surface  prepared  for 
them  ;  the  motion  is  small,  as  the  pipes  are  long,  and  the  vertical 
motion  of  the  valve  is  not  great.  The  valve  is  driven  by  two 
eccentrics,  one  on  each  side  of  the  cylinder,  with  rods  taking  pins 
fitted  to  the  top  cast-iron  ring.  The  steam  cylinder  is  placed 
on  the  top  of  the  blowing  one,  and  is  fitted  with  a  common  valve, 
with  sufficient  lap  to  cut  off  the  steam  at  one-half  of  the  stroke. 
The  piston-rod  crosshead  is  fitted  with  two  connecting  rods  taking 
the  cranked  shaft,  the  crosshead  working  in  suitable  guides.     Two 

1  Section  of  Air  Valve.  —  a,  Valve,     b,  Plate  for  connecting  valves. 


28o  MODERN   STEAM    PRACTICE. 

fly  wheels  are  fitted,  thus  less  diameter  is  required  for  a  given 
weight,  and  it  is  found  desirable  to  limit  the 'weight  to  i  ton.  When 
the  means  of  transport  is  difficult  no  part  of  the  engine  should 
exceed  this  weight.  These  engines  do  not  require  massive  and 
expensive  foundations;  they  can  rest  on  balks  of  timber  with  merely 
a  few  bolts  to  hold  them  down.  They  can  also  be  driven  at  a  high 
velocity,  owing  to  the  action  of  the  valve  preventing  all  blow  and 
jar  in  the  working,  when  the  lap  and  lead  are  properly  adjusted: 
a  pair  of  them  can  be  worked  together,  the  cranks  being  at  right 
angles  to  each  other,  causing  great  uniformity  in  the  flow  of  the 
blast,  and  no  regulator  is  required.  A  pair  of  these  engines,  with 
a  piston  speed  of  400  feet  per  minute  blowing  3600  cubic  feet  of 
air,  make  a  very  compact  arrangement  for  small -power  blowing 
engines. 

HORIZONTAL  BLOWING   ENGINE. 

Horizontal  high-pressure  blowing  engines  have  been  extensively 
used.  In  the  following  example  (Fig.  1 88),  which  is  one  of  the  largest 
description,  the  diameter  of  the  steam  cylinder  is  4  feet  3  inches, 
with  a  stroke  of  9  feet.  The  blowing  cylinder  has  a  diameter  of 
108  inches,  and  the  length  of  stroke  is  the  same  as  for  the  piston  of 
the  steam  cylinder,  the  number  of  strokes  being  about  twenty-two, 
giving  a  total  speed  of  396  feet  per  minute. 

The  steam  valves  (Fig.  189)  are  of  the  piston  type,  which  are  very 
generally  used  for  blowing  engines,  because  they  are  perfectly 
balanced,  and  therefore  suffer  little  wear  and  tear,  which  is  a  great 
desideratum  with  engines  requiring  to  go  day  and  night  for  a  length- 
ened period.  The  valves  are  cast  together  with  a  pipe  connection, 
each  piston  is  packed  with  a  single  ring,  which  is  kept  up  to  the 
working  face  by  a  spring;  the  junk  rings  are  each  secured  with  a 
single  nut  having  a  thread  cut  on  the  valve  spindle,  which  is  central 
with  the  valves.  The  valve  casing  is  a  circular  casting;  the  steam 
is  admitted  between  the  valves,  and  the  exhaust  takes  place  at  both 
ends.  The  valves  are  arranged  so  as  to  make  the  steam  ports  as 
short  as  possible;  and  there  is  an  annular  ring  round  the  piston,  to 
give  free  entrance  and  exit  for  the  steam  all  round  the  circumfer- 
ence of  the  valves.  The  valve  rod  passes  through  stuffing  boxes  at 
both  ends  of  the  casing,  and  as  the  valves  are  placed  at  the  side  of 
the  steam  cylinder,  the  motion  for  working  them  is  direct,  a  plain 


STATIONARY   ENGINES. 


281 


282 


MODERN   STEAM   PRACTICE. 


eccentric  and  rod  being  adopted,  having  a  joint  placed  close  up 
to  the   guide  block   for  the   valve   rod,    carried    up   considerably 


Fig.  189. — Steam  Valve  for  Horizontal  Blowing  Engine. 
A,  Valve.      B,  Valve  rod.      c.  Packing  ring.       d,  Connecting  pipe. 

beyond  the  stuffing  box,  thus  lessening  the  length  of  the  eccentric 
rod. 

The  steam  cylinder  (Fig.  190)  is  of  the  ordinary  description,  with 
projections  cast  on  for  bolting  down  to  the  bed  plate.  It  is  provided 
with  a  cover  and  stuffing  box  at  each  end,  through  which  the  piston 
rod  passes,  with  recesses  for  the  nut  and  collar  that  secures  the  piston 
to  the  rod.  The  piston  should  be  as  light  as  practicable,  and  its 
ends  strengthened  with  ribs  in  the  casting;  the  packing  is  metallic, 
held  up  to  the  face  with  a  number  of  short  flat  springs;  the  junk 
ring  is  bolted  down  with  bolts  and  nuts  recessed  in  the  piston  in 
the  usual  manner.  To  prevent  radiation  the  cylinder  and  valve 
casing  are  covered  with  felt  and  wood  lagging;  and  straps  of 
wrought  iron  or  brass  are  used  to  bind  securely  the  wooden  strips 
placed  over  the  felt.  The  main  crank  is  of  cast  iron,  and  is  con- 
nected to  the  piston  rod  by  a  wrought-iron  rod,  with  straps,  jibs, 
and  keys  at  both  ends,  having  a  wrought-iron  crosshead  and  gud- 
geon with  blocks  working  in  cast-iron  motion  bars ;  thus  one  end 
of  the  piston  rod  is  truly  guided,  while  at  the  back  end  it  takes  a 
crosshead  working  into  a  slipper  guide,  to  which  the  piston  rod  for 
the  blowing  cylinder  is  securely  cottered. 

The  blowing  cylinder  (Fig.  191)  is  a  plain  casting,  with  side  flanges 
for  bolting  it  to  the  bed  plate  which  runs  the  entire  length  of  the 


STATIONARY   ENGINES. 


283 


engine.     The  piston  rod  passes  through  both  ends  of  the  cylinder, 
and  is  guided  with  crossheads  and  sHpper  guides,  as  aheady  ex- 


E   > 


plained.     The  diameter  of  the  piston  rod  is  greater  than  that  for 
the  steam  cylinder,  which  tends  to  carry  up  the  piston.     Some 


284 


MODERN   STEAM   PRACTICE. 


engines  of  this  class  have  a  trunk  passing  through  both  ends  in  a 
similar  manner,  by  which  means  more  bearing  surface  is  obtained 
for  carrying  up  the  piston,  it  being  supported  as  it  were  with  a 
tubular  beam, — thus  reducing  the  wear  and  tear  in  the  cylinder. 
The  air  valves  are  arranged  in  the  covers,   and  consist  of  round 

discs,  working  on  suitable  grat- 
ings, with  guards  to  limit  the  lift. 
The  valves  for  the  entrance  of 
the  air  are  placed  centrally  round 
the  stuffing  box  for  the  piston 
rod,  that  part  of  the  cover  being 
strongly  ribbed  in  the  casting; 
and  an  annular  chamber  is  cast 
round  the  circumference  of  the 
cover,  which  is  fitted  with  valves 
of  the  same  description  for  the 
exit  of  the  air, — a  large  opening 
being  left  at  the  bottom,  in  con- 
nection with  the  main  pipes,  &c., 
to  the  furnaces.  Small  covers 
are  fitted  for  the  convenience  of 
inspecting  the  exit  valves. 

This  engine  is  used  to  blow  air 
to  two  furnaces;  the  area  of  the 
blowing  piston  is  6yo']2  square 
feet,  and  it  discharges  24,976 
cubic  feet  per  minute.  As  ample 
rubbing  surface  in  all  the  work- 
ing parts  has  been  well  consi- 
dered, this  engine  has  been  found 
to  be  very  economical  in  the 
matter  of  repairs.  The  diameter 
of  the  fly  wheel  is  about  2 1  feet ; 
and  as  the  whole  of  the  ma- 
chinery is  built  up  on  one  frame, 
from  end  to  end,  the  foundation  is  laid  in  brickwork,  with  about 
2  feet  of  stonework  on  the  top.  This  class  of  engine  is  certainly 
the  cheapest  that  can  be  supplied  for  heavy  work ;  and  the  engine 
house  need  not  be  so  large  as  for  the  overhead  -  beam  arrange- 
ments. 


Fig.  191. — Blowing  Cylinder  and  Cover. 


STATIONARY   ENGINES.  285 


ROLLING-MILL   ENGINES. 

Engines  for  driving  rolling  mills,  &c.,  should  be  made  strong,  as 
they  require  to  run  for  weeks  without  stopping.  The  examples 
shown  in  Figs.  192  and  193,  of  engines  erected  at  the  Dowlais  Iron 
Works,  are  unusually  strong.  Cast  iron  is  largely  used  in  their  con- 
struction. They  are  of  the  high  pressure  kind,  coupled  at  right 
angles  to"  each  other. 

The  steam  cylinders  are  45  inches  in  diameter,  with  a  stroke  of 
10  feet,  making  24  double  strokes  per  minute.  Each  cylinder  has 
a  common  slide  valve  of  brass,  worked  by  an  eccentric  on  the  main 
shaft.  The  expansion  valves  are  of  the  gridiron  sort,  worked  by  a 
cam  on  the  main  shaft,  the  steam  being  cut  off  at  about  one-third 
of  the  stroke;  an  arrangement  is  made  for  throwing  these  valves 
out  of  gear  when  the  engines  are  doing  heavy  work.  Each  engine 
is  fitted  with  a  small  slide  valve  to  be  worked  by  hand,  for  the 
purpose  of  starting  and  reversing. 

The  framing  under  the  engines  and  machinery  is  of  cast  iron, 
and  consists  of  four  lines,  each  75  feet  long,  12  feet  high,  and 
21  inches  wide,  the  whole  weighing  about  850  tons.  The  whole 
engines  are  thus  self-contained, — a  very  important  point  in  this 
class  of  engine. 

Each  beam  is  in  two  parts,  each  part  weighing  about  17  tons, 
making  the  total  weight  of  the  beam  when  complete  about  yj  tons. 
The  two  beams  are  supported  upon  eight  columns,  24  feet  long 
and  2^2  feet  in  diameter,  securely  fastened  at  the  bottom  in  deep 
jaws  cast  upon  the  framing.  Upon  the  top  of  each  group  of  four 
columns  is  a  large  and  heavy  entablature  plate,  which  carries  the 
pillow  blocks  for  the  main  gudgeons.  Each  column  passes  through 
the  entablature,  the  bosses  at  the  junction  being  24  inches  deep; 
these  are  bored  out,  and  the  tops  of  the  columns  turned,  so  as  to 
insure  a  perfect  fit.  The  pillow-block  brasses  are  secured  and 
tightened  up  by  wrought-iron  keys  in  the  jaws  of  the  pillow  blocks, 
which  are  bolted  down  on  the  entablature,  and  further  secured  with 
joggles  and  keys. 

The  connecting  rods  are  of  oak,  with  wrought-iron  straps;  an 
experience  of  forty  years  having  proved  that  such  rods  are  the 
best,  and  more  easily  kept  in  repair  than  cast-iron  ones,  which  are 


2S6 


MODERN   STEAM   PRACTICE. 


liable  to  break,  while  wrought-iron  rods  are  much  heavier.     The 

m 


oak  rod,  strapped  with  wrought  iron,  is  better  calculated  to  stand 


STATIONARY   ENGINES. 


287 


the  severe  and  sudden  strain,  as  the  material  possesses  an  elasticity 
which  tends  to  lessen  the  shock. 


The  driving-wheel  shaft  is  of  cast-iron,  24  inches  in  diameter; 


288 


MODERN   STEAM   PRACTICE. 


Fig.  194. — Details  of  Fly  Wheel,  Framing,  and  Pinions. 
A,  Fly  wheel,  showing  mode  of  fastening.     B,  Frame,  showing  mode 
of  fastening,     c.  Pinions. 


the  fly-wheel  shaft  is  also  of  cast  iron,  with  bearings  21  inches  in 
diameter.    The  diameter  of  the  driving  wheel  is  25  feet  at  the  pitch 

line;  the  pitch  is  7 
inches,  and  the  width 
of  the  teeth  27  inches. 
The  diameter  of  the 
spur  wheel  or  pinion 
on  the  fly-wheel  shaft 
is  6  feet,  and  the  teeth 
are  strengthened  by  a 
flange  running  up  to 
their  points  on  each 
side.  The  fly  v/heel 
on  the  mill  shaft  is 
21  feet  in  diameter, 
and  weighs  about  30 
tons;  it  makes  up- 
wards of  100  revolutions  per  minute.  The  whole  of  the  fastenings 
both  of  the  wheels  and  framing  are  of  dry  oak  and  iron  wedges. 

The  blowing  engines  of  this  firm,  described  in  the  preceding 
pages,  are  of  650  nominal  horse-power,  and  weigh  about  300  tons, 
including  the  bed  plate;  the  pair  of  rolling-mill  engines  are  of 
1000  nominal  horse-power,  and  contain  about  lOOO  tons  of  metal, 
or  I  ton  per  nominal  horse-power.  This  is  very  nearly  double  the 
ordinary  proportion,  but  it  is  the  practice  of  this  firm  to  make  their 
engines  very  strong,  so  as  to  avoid  if  possible  the  need  of  stoppages 
of  the  works  caused  by  a  break-down  of  the  machinery.  The  steam 
for  the  rolling-mill  engines  is  supplied  by  six  Cornish  boilers,  each 
44  feet  long  and  7  feet  in  diameter,  with  a  4-feet  tube.  The  whole 
of  the  plates  are  best  Stafi"ordshire,  y^  inch  thick;  the  total  weight 
of  the  boilers  is  about  120  tons. 

These  engines  can  drive  one  rail  mill  capable  of  turni-ng  out 
1000  tons  of  rails  per  week,  another  mill  capable  of  making  700  tons 
of  rails  or  roughed-down  per  week,  and  one  bar  or  roughing-down 
mill,  capable  of  making  200  tons  per  week;  thus  turning  out  a 
total  of  about  2000  tons  of  iron  per  week.  Two  blooming  mills 
with  three  high-rolls  and  two  hammers,  are  also  worked  by  the 
same  engines.  The  saws  and  small  machinery  are  driven  by 
separate  engines,  as  also  the  punching  and  straightening  machines. 
The  roofs  cover  a  space  of  240  feet  by  210  feet,  and  are  formed  of 


STATIONARY   ENGINES. 


289 


corrugated  black  plates,  No.  14  wire  gauge  in  thickness.  The  spans 
are  50  feet,  the  roofs  being  supported  upon  lattice  girders  of  an 
average  length  of  45  feet.  The  position  of  the  columns  is  shown 
on  the  ground  plan,  Fig.  195  ;  and  it  will  be  observed  that  the  entire 


Fig.  195. — General  Arrangement  of  Rolling  Mill.     Ground  Plan. 


mill  floor  is  free  from  obstruction.     The  flooring  is  of  cast-iron 
plates,  I  inch  thick. 

It  had  long  been  felt  that  the  power  of  rolling  wrought  iron  of 
large  section  and  great  lengths  had  not  kept  pace  with  the  require- 
ments of  engineers,  who  were  frequently  hampered  in  their  designs 
by  the  impossibility  of  obtaining  iron  of  sufficient  dimensions.  For 
engineering  works  of  any  magnitude  bars  of  great  length,  consider- 
able width,  and  moderate  thickness  are  often  required ;  and  in  the 
ordinary  mode  of  rolling,  the  length  and  width  of  the  bar  are 
measured  by  the  power  of  the  engine  and  the  time  occupied  in 

rolling.     It  is  obvious  that  to  finish  a  bar  quickly  it  is  necessary 

19 


290 


MODERN    STEAM   PRACTICE. 


that  it  should  be  rolled  in  two  directions  to  prevent  delay;  and 
long  and  heavy  bars  can  be  thus  rolled  only  by  an  engine  of  enor- 
mous power,  such  as  the  large  combined  engines  we  have  described. 
A  simple  arrangement  of  rolls  for  working  in  two  directions  has 
been  adopted,  by  which  means  large  bars  of  thin  section  are  finished 


ImA 


Fig.  196. — Arrangement  of  Rolls  for  rolling  in  two  directions. 

A  A,  Rolls  driven  from  fly-wheel  shaft,     b  b,  Rolls  driven  from  the  fly-wheel  shaft  by  a  pair  of 
wheels  c  c,  Fig.  194. 

in  one  heat,  as  it  is  impossible  to  get  such  large  bars  into  the  fur- 
nace to  re-heat.  In  ordinary  rolling  so  much  time  was  lost  in 
bringing  back  the  bar  over  the  top  of  the  rolls  that  it  was  found 
impossible  to  make  the  larger  sizes  required  for  modern  work,  and 
the  plan  was  therefore  adopted  of  having  a  second  pair  of  rolls 
running  in  the  opposite  direction,  placed  at  the  back  of  the  first 
rolls,  as  seen  in  Fig.  196,  the  lower  one  of  the  second  pair  being 
raised  just  enough  above  the  upper  one  of  the  first  pair  to  clear 
the  bar  in  coming  through,  and  the  bar  is  passed  back  through  the 
second  rolls,  and  then  through  the  third,  fourth,  and  fifth  rolls  as 
may  be  required,  as  shown  by  the  figures  in  the  engraving.     By 


ROLLING    MILL    ENGINES. 


OUND    REVERSING    ROLLIN 


,    STEEL  COMPANY    OF   SCOTLAND 


ilDE,    NEAR   GLASGOW. 


STATIONARY   ENGINES.  29 1 

this  means  much  time  is  saved  over  the  ordinary  method,  with 
the  additional  advantage  of  being  able  to  manufacture  bars  up 
to  60  feet  long,  for  deck  beams  and  keels  of  iron  ships,  in  one 
length  without  a  weld,  which  can  only  be  effected  by  having  a  high 
speed  of  the  rolls  so  as  to  complete  the  work  before  the  bar  gets 
too  cold.  Reversing  gear  has  been  used  for  the  rolls,  but  it  is 
not  to  be  recommended  for  them  when  running  above  forty-five 
revolutions  per  minute,  on  account  of  the  violent  shock  in  reversing 
the  motion  at  a  higher  speed.  To  roll  the  length  required  for  the 
above  purposes  the  speed  at  the  Dowlais  Iron  Works  is  nearly 
three  times  as  great,  the  ordinary  rolls  running  at  120  revolutions 
per  minute,  and  the  others  for  large  sections  at  no  revolutions, 
the  rolls  being  of  the  full  size — 21  inches  in  diameter. 


COMPOUND    REVERSING   RAIL   MILL   ENGINES, 

AT  HALLSIDE  STEEL  WORKS,   NEAR  GLASGOW.    (See  Plate.) 

"  The  engines  are  of  the  compound  direct-acting  horizontal  type, 
and  have  two  high-  and  two  low-pressure  cylinders,  whose  diameters 
are  respectively  31  inches  and  50  inches,  while  the  length  of  stroke 
is  5  feet.  They  act  directly  on  the  rolls,  by  which  arrangement 
there  is  obtained  a  very  high  speed  in  the  rolling  operation  with  a 
comparatively  limited  speed  in  the  engines,  the  latter  making  from 
fifty  and  sixty  revolutions  per  minute.  In  each  case  the  high- 
pressure  is  placed  in  rear  of  the  low-pressure  cylinder,  with  which 
it  is  connected  by  means  of  an  intervening  receiver.  Laid  upon 
a  bed  of  hard  and  tough  blue  clay,  the  foundation  of  these  engines 
— the  total  weight  of  which  is  some  300  tons — consists  of  a  solid 
mass  of  Portland  cement  concrete,  12  feet  or  14  feet  in  thickness, 
and  weighing  between  500  tons  and  600  tons.  To  this  foundation 
is  fixed  the  soleplate,  which  weighs  about  60  tons,  and  carries  the 
two  pairs  of  cylinders,  as  also  the  two  main  frames.  The  latter, 
which  are  of  the  box  form,  are,  as  will  be  seen  in  the  Plate, 
arranged  so  as  to  form  a  direct  connection  between  the  low-pressure 
cylinders  and  the  crankshaft,  while  the  pedestals  for  the  crankshaft 
bearings  are  cast  solid  with  them.  Under  each  crankshaft  bearing 
the  frame  has  a  strong  foot,  which  is  not  only  bolted  down  to  the 
soleplate  by  two  holding-down  bolts,  but  which  has  in  addition  on 


292 


MODERN   STEAM   PRACTICE. 


each  side  oval  bosses,  on  which  there  are  shrunk  steel  hoops  for 
tying-  down  the  central  part  of  the  foot  to  the  soleplate;  while  the 
ends  are  keyed  in  between  strong  snugs  cast  on  the  same  plate. 
Each  crankshaft  bearing 
is  provided  with  four 
brasses,  one  above  and 
one  below,  and  one  on 
each  side.  The  fore  and 
aft  parts  are  fitted  with 
movable  wedge  blocks 
which  take  up  the  wear, 
these  blocks  being  pro- 
vided with  slotted  eyes, 
and  being  suspended  by 
means  of  bolts,  which 
are  flat-headed,  but  of  a 
circular  form.  The  top 
brasses  are  adjusted  with 
set  screws,  and  both  they 
and  the  bottom  brasses 
are  held  in  position  by 
the  top  cover,  which 
bridges  over  the  opening 
in  the  frame.  On  each 
side  of  this  opening  there 
is  a  strong  dovetailed 
projection  over  which  the 
cover  is  placed.  Itself  a 
strong  steel  forging,  this 
cover  is  most  securely 
keyed  in  position,  in  ad- 
dition to  which  it  is 
bolted  down  hard  and 
fast.     The  arrangements 

just  noticed  result  in  the  most  rigid  connection  being  effected 
between  the  fore  and  aft  portions  of  the  engine  framing.  Be- 
tween the  crankshaft  bearings  and  the  guide  bars  the  frames  have 
cast  on  them  horn-like  brackets,  through  which  pass  stay  bolts 
carrying  suitable  distance  pieces,  thereby  securing  at  this  part 
of  the  framing  an  amount  of  rigidity  quite  equal  to  that  which 


STATIONARY   ENGINES.  293 

exists  in  the  anterior  portion.  Inside  the  main  frames  there  are 
fixed  the  slide  bars,  which  are  adjustable,  top  and  bottom,  for 
the  purpose  of  taking  up  the  wear.  The  upper  one  is  made  plane 
throughout,  but  the  lower  one  is  of  a  trough  shape.  They  are 
made  of  the  best  forged  steel,  as,  indeed,  are  all  the  working  parts 
of  the  engines. 

The  high-pressure  cylinders  are  each  fitted  with  a  liner,  the 
space  between  this  and  the  cylinder  casting  proper  forming  a  steam 
jacket;  the  low-pressure  cylinders,  however,  are  not  jacketted.  At 
their  forward  ends  each  of  the  low-pressure  cylinders  is  solid,  and  is 
provided  with  a  bracketted  flange  where  it  is  in  contact  with  the 
main  frames ;  and  connection  between  the  frames  and  the  cylinder 
ends  is  effected  by  means  of  bolts,  no  studs  being  used. 

The  valves  of  these  engines  are  of  the  double-piston  type.  The 
steam  ports  in  the  valve  casings  have  triangular  openings  into  the 
valve  cylinders,  the  valve  pistons  having  a  91^  inch  stroke,  and 
being  fitted  with  broad  packing  rings  which  are  furnished  with 
cylindrical  springs  of  a  V  shape.  A  tight-working  piston  is  thereby 
obtained,  no  escape  of  steam  having  been  observed  at  any  pressure 
yet  employed.  The  object  airned  at  in  employing  this  type  of 
valve  was  to  relieve  the  valve  motion  of  the  severe  tear  and  wear 
resulting  from  the  use  of  unbalanced  flat-faced  valves. 

The  valve  casings  are  placed  on  the  sides  of  the  cylinders  in 
order  that  they  may  be  easily  got  at  for  inspection  or  in  case  of 
repairs  being  necessary.  The  receiver  formerly  mentioned  as  inter- 
vening between  the  high-  and  low-pressure  cylinders  of  each  engine 
is  immediately  underneath  the  valve  casings,  and  serves  to  catch 
up  any  water  that  might  otherwise  enter  the  cylinders.  The  valve 
spindles  are  of  steel,  and  are  jointed  together  by  means  of  a  box 
coupling  provided  with  cotters — an  arrangement  which  allows  of 
the  pistons  and  spindles  being  easily  withdrawn  for  repairs  and 
replaced  in  position. 

Steam  is  admitted  into  the  high-pressure  cylinder  by  the  piston 
valve  entering  between  the  pistons  of  the  valve,  and  exhausting  at 
each  end  into  the  receiver.  The  distribution  of  the  steam  into  the 
low-pressure  cylinder  is  similarly  effected  by  its  valve,  the  steam 
entering  at  the  middle  of  the  valve,  and  exhausting  at  each  end  as 
before.  On  the  top  of  the  low-pressure  valve  casing  there  is  placed 
a  small  auxiliary  slide  valve,  which  is  worked  from  the  link  motion 
of  the  main  valve,  and  is  in  direct  communication  with  the  steam 


294  MODERN   STEAM    PRACTICE. 

of  full  boiler  pressure,  so  that  in  the  event  of  the  rolls  failing  at  any 
time  to  '  bite '  when  the  ingot  or  bar  in  process  of  rolling  is  about 
to  enter,  the  driver  can  at  once  admit  steam  at  full  pressure  direct 
from  the  boilers  upon  the  pistons  in  the  low-pressure  cylinders,  and 
turn  it  off  instantaneously  when  the  desired  effect  is  accomplished. 
The  valve  just  referred  to  consists  of  a  D-slide  working  on  the  face 
of  a  grid  plate  having  openings  similar  to  the  valve  ports,  and 
serving  the  purpose  of  a  shut-off  valve  as  well  as  a  slide  valve.  The 
motion  of  this  valve  is  governed  by  the  general  link  motion  of  the 
engines,  thereby  insuring  that  there  shall  never  be  any  uncertainty 
as  to  the  admission  of  the  steam  pressure  on  the  proper  side  of  the 
piston.  Both  high-  and  low-pressure  cylinders  are  provided  at  each 
end  with  spring  escape  valves. 

The  crankshaft,  which  weighs  105^  tons,  is  a  fine  steel  forging, 
and  extends  from  the  coupling  to  the  mill  to  the  right-hand  engine, 
or  engine  furthest  from  the  mill. 

The  crankshaft  bearings  are  18  inches  in  diameter,  as  are  also 
the  crank-pins. 

The  several  levers  by  which  the  operation  of  starting,  reversing, 
&c.,  are  controlled,  are  all  within  a  few  inches  of  each  other,  and 
there  is  nothing  to  intercept  the  driver's  view  of  what  is  going  on 
at  the  rolling  mill,  in  front  or  in  rear,  or  of  the  whole  surface  of  the 
engines.  The  engines  are  started  and  reversed  by  the  aid  of  a  small 
steam  cylinder  provided  with  cataract  regulation. 

The  engines  we  have  been  describing  drive  a  26-inch  mill.  They 
are  worked  with  steam  at  120  lbs.  pressure,  and  are  capable  of 
easily  developing  3000  horse-power. 

The  steam  for  driving  the  engines  we  have  been  describing  is 
supplied  by  boilers  of  the  locomotive  type,  these  being  three  in 
number. 

The  boilers  have  barrels  6  feet  2^  inches  in  diameter,  and  each 
contains  336  tubes,  2^  inches  in  diameter  by  12  feet  long.  The 
tube  surface  in  each  boiler  is  thus  2640  square  feet,  while  the  firebox 
surface  is  iyij4  square  feet  and  the  firegrate  area  30  square  feet. 
The  fireboxes  are  each  provided  with  a  longitudinal  mid-feather; 
and  in  each  case  the  roof  of  the  inside  firebox  is  stayed  direct  to 
the  casing  by  steel  stays.  The  two  front  rows  of  these  stays  are 
arranged  with  their  upper  ends  in  sockets,  so  as  to  allow  for  the 
expansion  and  contraction  of  the  tubeplate  of  the  firebox.  Arrange- 
ments are  made  for  a  firebrick  arch  resting  on  angle-irons.     No 


STATIONARY   ENGINES.  295- 

brick  setting-  is  required  for  the  boilers,  which  are,  instead,  set  on 
cast-iron  frames,  which  serve  as  stands  on  each  side  of  the  firebox 
and  smokebox,  in  this  way  again  giving  allowance  for  freedom  of 
motion  during  expansion  and  contraction.  Each  boiler  is  supplied 
with  a  couple  of  Cockburn's  234^  inch  diameter  open-flow  pendulum 
valves,  each  of  which  is  loaded  to  a  working  pressure  of  120  lbs.  per 
square  inch.  Prior  to  delivery  the  boilers  were  experimentally  sub- 
jected to  a  water  pressure  of  250  lbs.  per  square  inch,  while  they 
were  also  tried  under  steam  to  the  pressure  just  mentioned.  They 
have  already  proved  themselves  to  be  excellent  steam  raisers. 
Practically  the  whole  of  the  material  of  these  boilers  is  steel;  the 
principal  exception  being  that  of  the  tubes,  which  are  of  iron."^ 


THE   CORLISS   ENGINE. 


An  engine  combining  economy  of  working  with  a  moderate  first 
cost  must  ever  be  of  primary  importance.  The  distribution  of 
steam  effected  by  the  ordinary  slide  valve  actuated  by  the  single 
eccentric  has,  after  long  trial,  been  found  to  yield  unsatisfactory 
results;  many  ingenious  improvements  have  been  adopted,  and 
amongst  these  is  the  "  Corliss  "  liberating  valve  gear,  named  after 
the  inventor. 

The  characteristic  features  which  are  common  to  all  the  forms  of 
liberating  valve  gear  may  be  thus  briefly  stated : — The  steam  is  cut 
off  almost  instantaneously  by  the  agency  of  some  force  suddenly 
called  into  play,  such  as  a  falling  weight  or  the  recoil  of  a  distended 
spring,  the  cut-off  being  regulated  to  the  amount  of  work  the  engine 
has  to  perform  directly  by  the  controlling  agency  of  the  governor 
and  the  cut-off  gear.  The  Corliss  engine  has  separate  pairs  of 
steam  and  exhaust  valves,  or  altogether  four  for  each  cylinder. 
They  are  of  the  cylindrical  type;  the  lower  of  them,  or  the  exhaust 
valves,  are  wrought  directly  from  the  eccentric  by  means  of  a  disc 
plate  and  levers  connected  with  the  valve  spindles;  they  remain 
open  during  the  whole  period  of  the  stroke,  and  are  not  affected  by 
the  cut-off  gear.  The  steam  valves  are  likewise  wrought  from  the 
disc  plate  by  levers,  which  open  the  valves  at  first,  and  so  distend 
a  steel  spiral  spring  whilst  the  steam  is  being  admitted,  till  on  the 

*  For  the  description  and  plate  we  are  indebted  to  Engineering,  vol.  xxvii. 


296 


MODERN   STEAM   PRACTICE. 


lever  reaching  a  certain  position  it  is  tripped  up  by  a  peculiarly- 


STATIONARY   ENGINES.  297 

shaped  toe-piece  liberating  the  spring,  which  by  its  recoil  instantly 
closes  the  valve.  To  guard  against  the  damage  that  might 
possibly  arise  from  the  too  violent  impact  of  the  spring,  it  is  closed 
in  a  dash  pot  or  vessel,  to  which  the  air  is  admitted  by  small 
holes,  but  prevented  from  escaping  freely,  and  which  forms  a 
cushion  to  check  the  impact  of  the  spring  and  bring  it  gradually  to 
rest.  The  governor  is  connected  with  the  cut-off  gear  by  levers, 
by  which  the  point  where  the  lever  is  tripped  may  be  altered  as  the 
cut-off  requires  to  be  hastened,  or  delayed  according  to  the  power 
required  from  the  engine.  No  throttle  valve  is  therefore  employed 
to  wire-draw  the  steam,  and  by  a  fall  of  pressure  (involving  a  direct 
loss  of  energy)  to  vary  the  power  given  out  by  the  engine;  but  the 
better  expedient  is  adopted  of  supplying  exactly  the  quantity  of 
steam  required  to  perform  the  work.  With  what  efficiency  this 
arrangement  answers  will  be  best  gathered  from  the  following 
instance: — In  a  spinning  factory  a  cogged  wheel  was  instantaneously 
stripped,  the  resistance  portion  of  the  work  which  it  drove  was  thus 
suddenly  removed;  but  so  perfectly  did  the  engine  draw  the  reduced 
quantity  of  steam  that  on  examination  not  a  single  thread  was 
found  to  be  broken.  Pumping  machinery  also  affords  another 
instance,  as  not  even  the  breaking  of  a  spear  rod  sensibly  affects  the 
speed  of  the  engine. 

As  has  been  already  stated  the  Corliss  engine  has  separate  steam 
and  exhaust  valves.  Not  to  mention  the  good  results  in  the  work- 
ing of  the  engines  which  are  due  to  this  arrangement,  the  separate 
valves  effect  a  direct  economy,  as  each  valve  is  kept  at  a  constant 
temperature,  and  the  steam  that  enters  through  them  directly  from 
the  boiler  is  not  cooled  down  as  it  would  be  if  it  entered  through 
the  same  passage  by  which  the  exhaust  steam  had  previously 
escaped,  neither  is  the  exhaust  steam  again  re-heated  by  contact 
with  the  hot  steam  valve ;  we  have  thus  a  direct  saving  of  heat, 
which  in  an  ordinary  slide-valve  engine  would  be  lost.  The  steam 
lost  by  clearance  when  performing  work  is  with  these  valves  reduced 
to  a  minimum.  To  test  thoroughly  the  actual  working  of  this 
engine  the  indicator  must  be  summoned  to  our  assistance;  and  the 
diagrams  obtained  from  it  will  enable  us  to  judge  to  what  extent 
the  theoretical  diagrams,  or  those  that  give  the  maximum  amount 
of  power  from  a  minimum  consumption  of  steam,  agree  with  those 
realized  in  practice.  The  conditions  necessary  to  insure  the  maxi- 
mum of  efficiency  may  be  thus  briefly  stated: — (i)  The  ports  must 


298 


MODERN   STEAM   PRACTICE. 


"m'^eZ  ^^^^-^  ftmnij 


stfi  ££  -sunss^uj-  joinu£ 


Vacuum.  13. 25  lb 


Averougc  Pressure-  lis 


'xms^aa^  96vu0Ay9C^ 


306 


f    E 


;9 


be  fully  open  during  the  whole  period  for  the  admission  of  steam. 


STATIONARY  ENGINES.  299 

(2)  The  cut-off  must  be  rapid,  (3)  The  back  pressure  must  be  a 
minimum.  (4)  The  steam  must  be  admitted  into  the  cylinder  at 
its  full  boiler  pressure  until  the  point  of  cut-off  is  reached.  In  the 
Corliss  diagrams  these  conditions  are  strictly  fulfilled.  The  admis- 
sion of  steam  is  indicated  by  a  nearly  perpendicular  line,  Figs.  198 
and  199,  and  the  cut-off  must,  with  the  means  employed,  be  practi- 
cally instantaneous.  The  diagrams  exhibit  a  remarkably  small  back 
pressure;  this  result,  along  with  the  constancy  of  pressure  main- 
tained until  the  point  of  cut-off  is  reached,  is  accounted  for  by  the 
large  area  that  can  be  given  to  the  steam  and  exhaust  passages,  as 
the  valves  employed  are  of  the  whole  breadth  of  the  cylinder. 

In  ordinary  engines  a  large  expenditure  of  power  is  required  to 
move  the  valves ;  this  loss  of  power  is  saved  in  the  Corliss  engine, 
as  one  man  with  an  ordinary  starting  bar  can  move  the  valves  of 
a  1000  horse-power  engine  against  the  full  pressure  of  steam.  As 
every  part  of  the  engine  is  readily  open  to  inspection,  no  difficulty 
is  experienced  in  examination,  and  repair  of  any  of  the  parts 
requiring  it;  but  in  practice  the  wear  is  found  to  be  very  slight. 
The  Corliss  engine  is  economical  in  the  matter  of  fuel,  its  con- 
sumption being  at  the  rate  of  2)/^  lbs.  per  horse  power  per  hour,  as 
proved  by  experiment, — a  result  that  must  go  far  to  recommend  it 
to  the  favourable  notice  of  manufacturers  requiring  steam-power. 


HIGH    AND   LOW   PRESSURE   COMBINED    BEAM 

ENGINE. 

The  high  and  low  pressure  combined  beam  engine  is  much  used 
where  great  regularity  of  motion  is  required,  more  especially  for 
driving  spinning  machinery.  This  regularity  of  motion  is  due  to 
the  steam  expanding  from  the  top  of  the  high -pressure  to  the 
bottom  of  the  low-pressure  cylinders,  and  vice  versa,  by  which  the 
jerk  at  the  commencement  of  the  stroke  of  the  piston  is  not  so 
much  felt  as  in  ordinary  engines  receiving  the  full  force  of  the 
steam  on  one  side  of  the  piston.  The  example  illustrated.  Fig.  200, 
consists  of  a  pair  of  engines,  coupled  at  right  angles,  for  driving  the 
machinery  at  the  Royal  Gun  Factory  at  Woolwich.  The  diameter 
of  the  fly  wheel  is  22  feet  at  the  pitch  line,  the  breadth  of  the  teeth 
12  inches,  and  the  pitch  3  inches,  gearing  into  a  pinion  4  feet 
6  inches  in  diameter. 


300  MODERN    STEAM    PRACTICE. 

Speed  of  the  engine  shaft 21  revolutions  per  minute. 

Do.  second  shaft 102  „  ,, 

Do.  third  shaft 150  ,  „ 

The  total  length  of  the  shafting  is  about  932  feet,  in  parallel  lengths, 
the  diameter  of  the  pinion  shaft  being  8  inches,  and  that  of  the 


Fig.  200. — High  and  Low  Pressure  Combined  Beam  Engines  of  80  horse-power  collectively. 

A,  High-pressure  cylinder.  b.  Low-pressure  cylinder.  c,  Condenser  and  cistern.  D,  Cold-water 
pump.  E,  Governor  and  feed-pump  rod.  F,  Spring  beam.  G,  Main  beam.  H,  Crank 
shaft.      I,  Pinion  shaft.      K,  Entablature.      L,  Columns.      M,  Stone  pedestal.     N,  Foundation. 

smaller  line  of  shafting  3  inches  at  the  end.  The  diameter  of  each 
high-pressure  cylinder  is  1 5  ^  inches,  stroke  of  piston  4  feet  6  inches; 
and  the  diameter  of  each  low-pressure  cylinder  is  31  inches,  with  a 
piston  stroke  of  6  feet.  The  valve  mechanism  for  those  engines  has 
already  been  described,  p.  102,  Fig.  5 1.  The  diameter  of  each  air 
pump  is  21  inches,  with  a  stroke  of  bucket  of  3  feet.  The  crank 
shaft  is  of  cast  iron,  the  journals  being  10  inches  in  diameter  and 
15  inches  long,  and  the  crank  pins  5^  inches  in  diameter  and 
75^  inches  long.  There  are  three  large  boilers,  35  feet  long  and 
7  feet  in  diameter,  with  two  inside  furnaces,  and  flues  running  the 
entire  length,  2  feet  6  inches  in  diameter,  with  return  wheel  flues  of 
brickwork.  The  steam  pressure  is  40  lbs.  per  square  inch,  and  the 
thickness  of  the  plates  is  as  follows : — 

Shell >^  inch  thick.     I     Flues ^  inch  thick. 

Ends ^        „  1    Rivets ^^  inch  in  diameter. 


STATIONARY   ENGINES.  3OI 


RULES  FOR  PUMPING  ENGINES. 

Horse-power. — The  standard  fixed  upon  to  represent  the  work 
of  one  horse  is  33,000  lbs.  raised  i  foot  high  in  one  minute.  To 
find  the  horse-power,  the  quantity  of  water  to  be  raised  is  reduced 
to  lbs.  and  multiplied  by  the  height  in  feet,  and  the  product  divided 
by  33,000  expresses  the  horse-power,  A  gallon  of  water  weighs 
exactly  10  lbs.,  thus  any  number  of  gallons  can  be  expressed  in 
lbs.  by  adding  a  cipher.     Hence  the  following  formula: 

Gallons  to  be  raised  per  minute  x  lox  height  _  i^o^se-power 
'     33000 

But  in  practice  about  one-fifth  must  be  added  for  the  friction  of  the 
engine.     Examples: — 

Supposing  1000  gallons  of  water  per  minute  is  required  to  be 
pumped  through  a  line  of  piping  to  a  height  of  1 20  feet,  and  the 
allowance  made  for  the  friction  in  the  pipes  is  equivalent  to  a  head 
of  water  of  150  feet:  required  the  horse-power.     Thus  we  have — 

,  Gals,  per  minute.  Lbs.    Height  in  feet. 

1000    X     10    X     150 

—     -  45  "45 

33000  ^•'  ^^ 

to  which  add  ^th  for  the  friction  of  the  engine  =    9*09 

54"54  horse-power. 

Again,  supposing  1,440,000  gallons  of  water  is  required  to  be 
pumped  up  in  the  24  hours  the  same  height,  we  have — 

Lbs.  raised 
I  foot  high  per 
Gals,  in  24  hours.      Lbs.      Height,    minute  =h. p.      mins.      hours. 

1,440,000    X    10    X    150    -7-    33000    X     (60    X    24)   =  45*45 
adding  as  before  -^th  for  friction  of  the  engine..... =     9*09 

S4"54  horse-power. 
Another  method  gives  the  horse-power  as  follows: — 

Gals,  in  24  hours.  Height.        Constant. 

1,440,000  X   150  -^  4,752,000  -  45-45 
■5th  added  =     9.09 


54 "54  horse-power. 

Supposing  the  quantity  is  given  in  cubic  feet  to  be  delivered  in 
the  24  hours,  at  the  same  height  as  before,  we  have — 


303  MODERN   STEAM   PRACTICE. 

Weight  Lbs.  raised 

Cubic  feet       of  a  cubic   Height    i  foot  high  per 
in  24  hours,     foot  in  lbs.  in  feet,     minute  =  H.  P.      mins.      hours. 

230,400   X   62-5   X    150    -7-    33000    X    (60  X   24)  =  45'45 
■|th  added =     9^09 


54"54  horse-power. 

The  power  required  to  raise  water  to  any  height  is  as  the  weight 
and  velocity  of  the  water.  Hence  the  following  rule:  Multiply  the 
perpendicular  height  of  the  water  in  feet  by  the  velocity  in  feet,  by 
the  square  of  the  pump's  diameter  in  inches,  and  then  by  '341  (the 
weight  of  a  column  of  fresh  water  i  inch  in  diameter  and  12  inches 
in  height),  dividing  the  product  by  33,000;  the  quotient  gives 
the  horse -power,  to  which  must  be  added  one -fifth  for  friction, 
and  say  one-fifth  for  loss,  or  two-fifths  in  all.  For  water-works' 
engines  20  per  cent,  is  allowed  for  friction,  &c.,  and  about  50  per 
cent  for  contingencies,  making  a  total  of  70  per  cent,  additional 
power. 

When  the  diameter  of  the  pump  and  velocity  of  the  water  are 
given,  to  find  the  quantity  discharged  in  gallons  or  cubic  feet  in 
any  given  time.  Multiply  the  velocity  of  the  water  in  feet  per 
minute  by  the  square  of  the  pump's  diameter  in  inches,  and  by 
•034  for  imperial  gallons,  or  '005454  for  cubic  feet,  and  the  product 
will  be  the  number  of  gallons  or  cubic  feet  discharged  in  the  time 
nearly. 

When  the  length  of  stroke  and  the  number  of  strokes  are  given, 
to  find  the  diameter  of  the  pump  and  the  horse-power  that  will 
pump  or  discharge  a  given  quantity  of  water  in  a  given  time.  First, 
multiply  the  number  of  imperial  gallons  of  water  to  be  discharged 
in  the  given  time  by  353,  or  the  number  of  cubic  feet  by  2201,  and 
divide  the  product  by  the  velocity  of  the  water  in  inches;  the 
square  root  of  the  quotient  will  be  the  pump's  diameter  in  inches. 
Second,  multiply  the  number  of  gallons  per  minute  by  10,  or  the 
number  of  cubic  feet  by  62 '5,  and  by  the  perpendicular  height  of 
the  water  in  feet,  divide  the  product  by  33,000,  then  add  ^th  to  the 
quotient,  which  will  give  the  horse-power  required.     Example: — 

Supposing  3,000,000  gallons  of  water  is  required  in  the  24  hours, 
the  stroke  being  10  feet,  making  12  strokes  per  minute — 

Gals,  in  the  24  hours,    mins. 

3,000,000  -i-   1440  =  2083  gallons  per  minute. 

Strokes 
Constant.     Stroke,  per  min. 

•03409    X    10   X    12   =  4 '09  divisor. 


STATIONARY  ENGINES.  303 

Gals,  per  min. 

—  \J  509*2,  the  square  root  of  which  is  22 '6  inches,  the  diameter  of  the  pump. 

One-fourth  more  than  the  above  is  usually  allowed  for  waste. 

Again,  supposing  the  number  of  gallons  per  minute  is  required — 

Square  of  the  Strokes 

Constant.       pump's  dia.     Stroke,    per  min. 

•03409     X    509*2    X     10    X     12    =    2083  gallons  per  minute  nearly. 
To  find  the  stroke  of  a  pump : — 

Square  of  the    Strokes 
Constant.       pump's  dia.,    per  min. 

•03409    X     509 '2    X     12    =    208 '2  divisor. 

Gals,  per  min. 

• — a-^-  =   10  feet  stroke  of  pump  nearly. 

Pumping  water  out  of  floating  and  other  docks.  —  Given  the 
quantity  in  tons  of  sea  water  (35  cubic  feet  to  the  ton),  the  height 
to  which  it  is  raised,  and  the  time  in  hours  that  is  allowed  to  dis- 
charge it,  to  find  the  horse-power.  Divide  the  quantity  in  tons  by 
the  number  of  hours,  which  gives  the  quantity  to  discharge  per 
hour,  and  this  divided  by  60  gives  the  quantity  to  discharge  per 
minute;  then  take  147  as  the  third  divisor  (147  tons  =  3 3,000  lbs., 
the  weight  raised  i  foot  high  per  minute),  which  gives  the  horse- 
power required  to  raise  the  total  quantity  i  foot  high:  multiply 
this  sum  by  the  height  at  which  the  water  is  discharged,  and  the 
quotient  is  the  horse-power  required  to  discharge  the  whole  amount 
in  the  given  time, — to  which  must  be  added  the  loss  from  friction 
and  waste. 

To  find  the  diameter  of  pump  required  to  discharge  a  given 
number  of  tons  of  sea-water  in  a  given  time,  with  a  certain  velocity 
(the  usual  speed  of  pump  bucket  being  160  feet  per  minute).  Mul- 
tiply the  quantity  by  the  constant  35,  and  divide  the  product  by 
the  speed  multiplied  by  the  time  in  hours,  and  then  by  60  for 
minutes;  the  quotient  is  the  pump  area  in  square  feet,  which  can 
be  subdivided  by  the  number  of  pumps  that  are  adopted. 

Method  for  finding  the  horse-power  of  single-acting  pumping 
engines. — Thus  supposing  the  water  is  pumped  into  an  air  vessel 
to  a  height  of  252  feet,  and  making  an  allowance  for  the  friction  in 
the  pipe — say  a  total  height  of  285  feet — the  diameter  of  the  plunger 
being  23  inches  and  the  stroke  10  feet,  making  10  strokes  per 
minute,  we  have  as  follows: 


304  MODERN   STEAM   PRACTICE. 

Area  in  sq.  feet. 
Diameter  of  the  plunger,  23  inches   =  2 '8852 

Weight  in  lbs.  of 
Plunger  area.     Lift  in  feet,     i  cubic  ft.  lbs. 

2-8852     X      285      X      62-5     =     51392  I 

Now  allowing  |^th  to  overcome  the  load  on  the  air  pump  and  the 
friction  of  the  engine,  we  have : 

Load  on  the    Length  of    Strokes 
piston  in  lbs.       stroke,     per  minute. 

61670  X   10  X   10  =  6167000 

,  6167000   „^  ,  , 

and -  =  ib6  horse-power  nearly. 

33000 

Approximate  rule  for  power  of  Cornish  engijie. — A  simple  rule  used 
by  some  engineers  for  calculating  the  quantity  of  water  delivered  from 
a  given  pump  is  as  follows : — Let  D  =the  diameter  of  the  pump,  then 

D^ 

—  represents  the  quantity  of  water  in  gallons  delivered  per  i  foot 

stroke  of  pump  nearly.     Let  S  =  the  speed  of  the  plunger  of  bucket 

D^ 
per  minute,  then  S  -7—=  the  number  of  gallons  delivered  per  mmute. 

Let  L  =  the  lift  in  feet,  and  the  horse-power  will  be  thus  obtained : 


L    I 


The  following  is  an  example: — Diameter  of  pump 
33000 
=  16,  stroke  of  pump=7-5,  number  of  strokes  per  minute  =  7*5, 
lift==:  190  fathoms  =  1 140  feet. 

Diameter  of  pump.  Speed. 

\ — ^  ^    —  8 '5  X  (7-5  X  7-5)  =  478  gallons  per  minute. 

„,,  ,    1  1140x10x478        ,    ,  , 

The  work  done  = — ^^-^  =  165  horse-power  nearly. 

33000 

This  rule  evidently  allows  for  waste  in  the   pump,  but  one -fifth 
must  be  added  to  the  sum  for  the  friction  of  the  engine. 

To  find  the  area  of  cylinder  reqicired  to  perform  a  given  amount 
of  work. — We  may  consider  the  mean  pressure  in  the  cylinder  as 
from  14  to  15  lbs.  per  square  inch,  and  the  velocity  of  the  piston 
from  80  to  85  feet  per  minute.  It  must  be  remembered  that  the 
pressure  per  square  inch  is  derived  from  the  actual  water  load 
divided  by  the  area  of  the  piston,  and  that  one-fifth  more  power 
must  be  allowed  for  friction.  Thus  the  pressure  multiplied  by  the 
velocity  equals  so  many  foot  pounds,  which  may  be  taken  on  an 
average  as  1000.  Therefore  we  divide  the  number  of  lbs.  of  water 
raised  i  foot  high  by  1000,  and  the  quotient  is  the  area  of  the 
cylinder  in  square  inches.     For  example: — Suppose  it  be  required 


STATIONARY   ENGINES.  305 

to  find  the  diameter  of  a  cylinder  of  a  Cornish  engine  sufficient  to 
raise  7,000,000  gallons  of  water  120  feet  high  in  24  hours.  Multi- 
ply the  number  of  gallons  by  10  (the  weight  in  lbs.  of  a  gallon  of 
fresh  water),  and  then  by  the  height ;  divide  the  product  by  the 
number  of  hours  reduced  to  minutes,  and  the  quotient  gives  the 
number  of  lbs.  raised  i  foot  high  per  minute,  which  divided  by  IQOO 
gives  the  area  of  the  cylinder.     Thus : 

7000000  X    10  X    120  ^  ^g^^^^^  ^  ^^^^  ^  ^333^ 

1440 
which  equals  86  inches  diameter  nearly;  to  which  must  be  added 
an  allowance  for  the  friction  of  the  engine.  The  divisor  used  may 
vary,  owing  to  the  pressure  and  velocity,  and  on  this  account  three 
eminent  firms  have  used  in  their  practice  926,  1113,  and  1140 
respectively;  but  the  average  of  a  number  of  Cornish  engines 
is  771. 

Steam  valves  for  Cornish  engine: — 

The  steam  valves =  -jV^  to  -sV^i  of  the  cylinder  area. 

The  equilibrium  valves r=  ^'^th  to -^Vh         ,,  „ 

The  exhaust  valves = -j^th  to  ^th         ,,  ,, 

To  find  the  duty  of  an  engine. — Supposing  an  engine  required 
3  lbs.  of  coal  per  indicated  horse-power  per  hour,  it  is  required  to 
find  the  duty  performed  by  112  lbs.,  or  a  cwt.  of  coal.  The  horse- 
power being  33,000  lbs.  raised  i  foot  high  in  a  minute,  or  1,980,000 
lbs.  raised  i  foot  high  in  an  hour — then  by  the  rule  of  three  we  have 

lbs.  lbs.  lbs.  lbs. 

3  :  1980000  :  :  112  =  73920000 

raised  i  foot  high  by  a  cwt.  of  coal  per  hour.  Formerly  the  duty 
was  estimated  by  the  bushel  of  coal,  weighing  94  lbs.,  but  it  is 
considered  most  convenient  to  adopt  the  112  lbs.  measure.  The 
average  duty  of  Cornish  engines  may  be  taken  at  60,000,000  lbs. 
raised  i  foot  high  in  one  hour  by  a  bushel  of  coal  weighing  94  lbs., 
or  71,489,361  lbs.  with  a  cwt.  or  112  lbs. 

The  power  required  to  overcome  the  friction  of  water  through  pipes. 
— When  water  is  required  to  be  pumped  through  a  long  line  of 
piping  an  allowance  is  generally  made  for  its  friction  in  transit.  The 
quantity  of  water  in  cubic  feet  per  minute,  and  the  diameter  and 
length  of  the  line  of  piping  being  given,  multiply  the  square  of  the 
quantity  in  cubic  feet  by  the  length  of  the  piping  in  feet,  and  divide 
the  product  by  the  constant  22  for  pumping  engine,  multiplied  by 

the  fifth  power  of  the  diameter  of  the  piping.     Thus,  supposing 

20 


306  MODERN   STEAM   PRACTICE. 

6 1  cubic  feet  of  water  requires  to  be  forced  to  a  height  of  178  feet, 
the  length  of  the  piping  being  8145  feet  and  the  diameter  of  the 
pipe  9  inches,  we  have — 


Cubic  feet.  Length  of  piping. 

61  X  61  =  3721  X  8145  =  30307505 


=  23*2  feet. 


22  X  (9x9x9x9x9)=   1299078 

as  the  additional  height  to  be  allowed  for  the  friction,  or  say  24  feet 
in  round  numbers;  thus  24  feet  added  to  the  height  the  water 
requires  to  be  pumped  equals  202  feet:  then  calculate  the  horse- 
power by  the  ordinary  method,  namely: 

Cubic  Weight  of  a 

feet.      Height,    cubic  foot. 

61    X    202    X    625 

• =  23"?  horse-power, 

33000  -^  -^  r         I 

to  which  add  one-fourth  for  loss,  and  the  product  is  29  horse-power 
nearly,  irrespective  of  the  friction  of  the  engine. 

Formula  to  find  the  extra  height  to  allow  for  friction  according 
to  the  above: — 

22  d' 

where  Q  is  the  quantity  in  cubic  feet  per  minute,  /  the  length  of 
the  line  of  piping,  and  d  the  diameter  of  the  pipes. 

Formula  to  find  the  horse-power  required  to  overcome  the  friction: 

140^* 
P  represents  the  horse-power  necessary  to  overcome  the  friction, 
/  the  length  of  the  pipe  in  inches,  Q  the  quantity  of  water  to  be 
delivered  in  one  second  in  gallons,  and  d  the  diameter  of  the  pipe 
in  inches.  The  formula  reads,  that  the  cube  of  the  quantity  in 
gallons  per  second  must  be  multiplied  by  the  length  of  the  line  of 
piping  in  inches,  dividing  the  product  by  the  constant  140  multi- 
plied by  the  diameter  of  the  piping  into  the  fifth  power. 
Delivery  of  water  in  pipes. — The  formula  is: 


W  =  472      /L 


/L  "    V       H 


where  D  equals  the  diameter  of  the  pipes  in  inches,  H  the  head  of 
water  in  feet,  L  the  length  of  pipe  in  feet,  and  W  the  cubic  feet  of 
water  discharged  in  a  minute. 

Hawkslefs  formula. — This  formula  is: 


-^=^7^'  <^V^ 


5D)*H. 


STATIONARY   ENGINES. 


307 


where  G  equals  the  number  of  gallons  delivered  in  an  hour,  L  the 
length  of  pipe  in  yards,  H  the  head  of  water  in  feet,  and  D  the 
diameter  of  pipe  in  inches. 

Weight  and  meastirement  of  water: — 

I  cubic  foot =62-5        lbs.  avoirdupois. 

I  cubic  inch —       '03617  „ 

I  gallon =  lO"  „ 

A  column  12  inches  high  and  i  inch  square...  =       "434  ,, 

A  column  12  inches  high  and  I  inch  diameter  =       '341  „ 

A  cylindrical  foot =  49'i  „ 

A  cylindrical  inch =       "02848  „ 

1 1 '2  imperial  gallons =  i  cwt. 

224  imperial  gallons =  I  ton. 

I"8  cubic  feet =  i  cwt. 

35  •84  cubic  feet =  i  ton. 

I  cubic  foot =  (>%  imperial  gallons. 

I  cylindrical  foot =5            >»  » 

To  find  the  thickness  of  pipes  for  conveying  water. — Multiply  the 
constant  -000054  by  the  head  of  water  in  feet,  and  then  by  the 
inside  diameter  of  the  pipe  in  inches,  to  which  add  ^  inch  for 
pipes  less  than  12  inches,  ^  inch  from  12  to  30  inches,  and  ^  inch 
from  30  to  50  inches  internal  diameter,  and  the  result  gives  the 
thickness.  Thus,  supposing  the  head  of  water  was  600  feet  and 
inside  diameter  of  the  pipe  15  inches, 

•000054  X  600  X  15  =  000  "486000  +  '5  =  '98, 
or  nearly  i  inch  as  the  thickness. 

Proportions  of  Socket  for  Standard  Pipes  for  Water  Supply. 


Internal  Dia- 

Thickness. 

Depth  of 

Thickness  of 

Space  for 

meter. 

Socket. 

Socket. 

Packing. 

inches. 

inch. 

inches. 

inch. 

inch. 

3 

5 

34 

3 

V 

3 

4 

5 

31 

1 
TB 

7 

5 

1 

3f 

tV 

^ 

6 

3 

34 

1 

■J 

A 

7 

3l 

1 

i^ 

8 

7 

34 

] 
"2 

A 

9 

^ 

4 

TS- 

\ 

10 

1 

4 

6 

■g- 

\ 

II 

1 

4 

5 

■J 

12 

9 

4 

\\ 

\ 

14 

5 

s 

4 

1  1 

I? 

To  find  the  weight  of  cast-iron  pipes. — To  find  the  weight  of  a 
lineal  foot,  square  the  outside  and  inside  diameters,  and  find  the 
difference,  then  multiply  the  result  by  2'45  lbs.,  which  is  the  weight 
of  a  circular  bar  i  inch  diameter  and  i  foot  long.  Supposing  the 
pipe  is  22  inches  diameter  outside  and  20  inches  diameter  inside, 


3o8 


MODERN    STEAM   PRACTICE. 


(22  X  22)  =  484  -  (20  X  20)  =  400  =  84  X  2*45  =  205  8  lbs.  nearly. 

Two  flanges  are  generally  reckoned  equal  to  i  foot  of  pipe. 

Pipes  for  pit  pumps. — The  most  approved  form  of  joint  for  pit  or 
pump  stand  pipes  is  the  spigot  and  faucet,  with  a  turned  face  on 
the  flanges  for  making  the  joint,  which  is  done  by  a  ring  of  wrought 


Fig.  200  A. — Pipes  for  Pit  Pumps. 

A,  Bottom  pipe.     B,  Top  pipe,     c,  Spigot,     d,  Faucet,     e,  Ring  of  wrought  iron.     F,  Flangfs. 
G,  Brackets,     h,  Bolt  and  nut.     I,  Holes.     K,  Faces  for  joint. 

iron  covered  with  plaiding  steeped  in  tar,  and  securely  bolted 
together  by  means  of  the  flanges  and  bolts.  The  spigot  is  accur- 
ately turned  a  little  less  in  diameter  than  the  faucet,  which  is 
bored  out  for  its  reception.  The  flanges  are  strongly  bracketed 
to  the  body  of  the  pipe,  and  the  holes  for  the  bolts  are  made 
slightly  oblong.  The  length  of  the  pipe  is  generally  about  9  feef 
over  the  flanges,  and  the  body  is  strengthened  with  two  or  more 
raised  rings  cast  on. 


STATIONARY   ENGINES. 


309 


Horse-power  of  an  engine. — The  horse-power  of  a  condensing 
beam  engine  may  be  found  theoretically  by  calculating  the  mean 
pressure  taken  from  the  steam  pressure  adopted  and  the  point  of 
cut-off  determined  on,  allowing  12  lbs.  per  square  inch  as  the  amount 
to  be  derived  from  the  vacuum.     Hence, 

Area  of  cylinder  in  sq.  in.  x  total  pressure  per  sq.  in.  x  velocity  of  piston  in  feet  per  minute 
"  ~  33000 

gives  the  horse-power  the  engine  will  work  up  to,  adding  to  this  an 
allowance  of  about  one-fifth  for  friction. 

Diameter  of  cylinder  and  length  of  stroke. — To  find  the  diameter 
of  cylinder  for  a  given  horse-power,  we  must  first  find  the  number 
of  square  inches  to  the  horse-power,  at  the  speed  determined  on, 
by  dividing  the  constant  33,000  by  the  total  pressure  (adding  one- 
fifth  for  friction)  multiplied  by  the  velocity  of  the  piston  in  feet  per 

minute.     Thus, 

33000 , 

Total  pressure  x  velocity  of  piston  in  feet  per  minute 

and  the  product  multiplied  by  the  total  horse-power  will  give  the 
full  area  of  the  cylinder  in  square  inches.  Where  great  exactness 
is  required,  add  one-half  of  the  area  of  the  piston  rod,  then  by  the 
table  of  areas  the  diameter  is  easily  ascertained.  The  stroke  of  the 
piston  ranges  from  2  to  2^  times  the  diameter  of  the  cylinder. 
Speed  of  piston  {varying  with  the  stroke) : — 


2  ft.  o  in.  stroke  =  160  feet  per  minute. 
26  „      =170  „ 

30,,     =180  „ 

36,,      =189  „ 

40  „     =200  „ 


4  ft.  6  in.  stroke  =  207  feet  per  minute. 
50,,      =215  „ 

60  ,,       :=228  ,, 

70,,       =245 

8       o  „     =256  „ 


Opening  of  port  by  valve. — The  opening  of  the  port  by  the  valve 
is  found  by  multiplying  the  area  of  the  cylinder  in  square  inches 
by  the  speed  in  feet  per  minute,  dividing  the  product  by  the  con- 
stant 10,000.  The  port  should  be  made  in  excess  of  this,  so  as  to 
give  a  free  exhaust;  the  breadth  depends  on  the  length  of  the  port, 
one-twentieth  of  the  area  of  the  cylinder  may  be  allowed  in  all 
cases.  For  the  exhaust  port  multiply  the  area  of  the  supply  port 
by  I  "5,  and  for  the  length  of  port  multiply  the  diameter  of  the 
cylinder  by  "6. 


3IO  MODERN   STEAM   PRACTICE. 


RULES   FOR  THE  BEAM   ENGINE. 

The  beam. — The  length  of  the  beam  should  not  be  less  than 
three  times  that  of  the  stroke,  and  its  breadth  one-half  of  the  stroke; 
for  the  breadth  at  the  ends  multiply  the  breadth  at  the  middle  by  '4. 
To  find  the  thickness  of  web  at  the  centre  multiply  the  total  pres- 
sure on  the  piston — i.e.,  steam  and  vacuum — by  one-half  of  the 
length  of  the  beam  in  inches,  and  divide  the  result  by  the  constant 
500  into  the  depth  in  inches;  the  quotient  is  the  sectional  area  in 
square  inches  for  cast  iron. 

Wrought-iron  tubular  beams: — 

/  =length 28  feet  8  inches. 

(^=depth 5    ,.    6     ,, 

a  =  area  of  bottom  flanges 56 '67  square  inches. 

C  =  constant 80 

'W=  breaking  weight  in  tons;  hence 

W=  -5 ^— ?s^v? =  870  tons, 

20 'OO 

as  the  breaking  weight  in  the  middle.  The  load  on  the  beam  being 
from  85  to  90  tons,  we  may  safely  consider  the  ratios  of  strength 
as  870 :  90,  or  nearly  10  to  i.  The  thickness  of  sides  for  a  beam  of 
the  above  dimensions  is  yi  inch,  supported  between  the  flanges 
with  T-iron  over  the  joints,  and  corresponding  strips  outside;  upper 
and  lower  webs  or  flanges  2  feet  wide,  with  four  plates  in  each, 
^  inch  thick,  rivetted  to  the  sides  with  double  angle  iron.  The 
centre  boss  is  cast  with  a  plate,  which  is  rivetted  to  the  sides;  the 
end  and  intermediate  bosses  have  also  cast-iron  plates.  Instead  of 
the  box  form  of  beam,  the  side  plates  are  sometimes  made  of 
sufficient  strength,  having  no  angle  irons  at  the  top  or  bottom,  but 
merely  secured  with  bolts  and  nuts,  and  sometimes  rivetted  to  the 
cast-iron  bosses.  The  diameter  of  the  main  gudgeon  is  generally 
one-fourth  of  the  diameter  of  the  cylinder,  and  for  the  piston-rod 
gudgeon  divide  the  cylinder  diameter  by  6*5 ;  or  they  may  be  cal- 
culated taking  them  as  round  beams  loaded  in  the  middle. 

To  find  the  versed  sine  described  by  the  beam  of  an  engine. — Divid- 
ing the  square  of  the  stroke  of  the  engine  by  8,  multiplied  by  the 
radius  of  the  beam,  gives  the  versed  sine  nearly,  viz.,  S^-i-  (8  x  R)  = 
versed  sine. 

A  ir  pump .  and  cofidenser. — The  air  pump  has  generally  a  stroke 


STATIONARY   ENGINES. 


311 


of  one-half  of  the  travel  of  the  steam  piston.  To  find  its  cubical 
contents,  divide  the  cubical  contents  of  the  steam  cylinder  by  4"3, 
When  the  stroke  of  the  pump  equals  one-half  that  of  the  steam 
piston,  to  find  the  diameter  of  the  pump,  in  usual  cases,  multiply 
the  diameter  of  the  cylinder  by  "j.  The  cubical  contents  of  the 
condenser  should  be  about  twice  the  capacity  of  the  air-pump. 

Cold-ivater  pump  ajid  injection  water. — To  determine  the  size  of 
the  cold-water  pump  we  must  first  ascertain  the  quantity  of  water 
required  for  condensation.  This  is  found  by  multiplying  the  tem- 
perature of  the  steam  by  "0034;  or  approximately  0"8  cubic  foot,  or 
5  gallons,  are  required  per  nominal  horse-power.  Multiply  this 
number  by  the  nominal  horse-power  of  the  engine,  and  then  by  the 
constant  2200;  divide  the  result  by  the  velocity  of  the  pump  bucket 
in  inches  per  minute,  and  the  square  root  of  the  quotient  is  the 
diameter  of  the  pump.  When  the  stroke  of  the  pump  is  one-half 
of  that  of  the  steam  piston,  the  usual  diameter  allowed  for  the  pump 
is  found  by  multiplying  the  diameter  of  the  cylinder  by  0*3.  The 
area  in  square  inches  of  the  injection  valve  should  be  from  -j^th  to 
T^g-th  the  number  of  cubic  feet  in  the  steam  cylinder. 

The  feed  pump. — To  find  the  water  required  to  be  delivered  by 
the  pump,  multiply  the  cubic  contents  in  feet  of  steam  in  the 
cylinder  for  an  entire  revolution  by  the  number  given  in  the  table 
of  cubic  inches  of  water  required  to  raise  a  cubic  foot  of  steam  at 
the  desired  pressure,  and  the  result  will  give  the  contents  of  a 
single-acting  pump  in  cubic  inches;  a  little  more  may  be  allowed 
for  waste,  &c.,  but  when  the  steam  is  cut  off  soon  in  the  cylinder 
no  additional  allowance  will  be  required. 


Table  of  the  Proportion  of  Water  to  Steam. 


Pressure  of 

steam 

Cubic 

inches  of  water 

Pressure  of  steam 

Cubic 

inches  of  water 

per  square 

inch. 

in  a  cubic  foot  of  steam. 

per  square 

inch. 

n^a  cubic  foot  of  steam. 

I 

= 

I -099 

45 

= 

3-700 

5 

= 

I  350 

50 

=. 

3-981 

ID 

= 

1-658 

55 

=. 

4-256 

20 

= 

2-258 

60 

= 

4-535 

25 

= 

2-552 

65 

= 

4-812 

30 

= 

2-842 

70 

= 

5 -052 

35 

= 

3-130 

75 

= 

5-317 

40 

= 

3 '415 

80 

= 

5-650 

The  diameter  of  the  valves  is  found  by  multiplying  the  diameter  of 
the  plunger  by  o-6. 

Piston  rod  and  connecting  rod. — To  find  the  diameter  of  the  piston 
rod  for  compressive  strain,  multiply  the  area  of  the  cylinder  by 


312  MODERN   STEAM   PRACTICE. 

the  steam  pressure,  and  divide  by  2240,  which  gives  the  area  of  the 
rod ;  and  for  tensional  strain  divide  by  4000,  which  gives  the  area 
at  the  weakest  part.  These  proportions  will  be  sufficient  for  all 
the  parts  subjected  to  direct  strain.  The  area  of  the  connecting 
rod  straps  equals  the  area  of  the  piston  rod ;  the  thickness  of  the 
strap  at  the  keyways  must  be  more  according  to  the  area  cut  out 
for  the  key.  The  depth  of  jib  and  cotter  equals  two-thirds  of  the 
diameter  of  the  connecting  rod  at  the  ends;  the  thickness  of  the 
jibs  and  keys  equals  one-fourth  of  the  rod  at  the  ends;  taper  of  the 
key  equals  ^  inch  to  the  foot ;  keyway  from  end  of  butt  equals  the 
breadth  of  the  jibs  and  cotters. 

Crank  shaft. — To  find  the  diameter  of  the  crank  shaft  when 
made  of  wrought  iron,  multiply  the  length  of  the  crank  in  inches 
from  centre  to  centre  by  the  total  pressure  on  the  piston,  and  divide 
the  sum  by  1206;  the  cube  root  of  the  quotient  will  be  the  diameter 
of  the  shaft. 

Crank  of  wrought  iron. — The  diameter  of  the  crank  pin  will  be 
found  by  multiplying  the  diameter  of  the  cylinder  by  "16;  for  the 
length  of  the  pin,  multiply  the  diameter  of  the  cylinder  by  •22. 
The  diameter  of  the  eye  for  the  crank  pin  is  twice  the  diameter  of 
the  pin.  The  length  of  the  boss  at  the  shaft  is  equal  to  the  diameter 
of  the  shaft ;  and  for  the  thickness  of  the  metal  around  the  shaft 
multiply  the  diameter  of  the  shaft  by  -37.  The  breadth  of  the  web 
at  the  crank-pin  end  and  journal  is  three-fourths  of  the  diameter  of 
the  respective  bosses,  and  its  thickness  is  five-eighths  of  their  width. 
These  proportions  are  for  low-pressure  engines,  with  a  steam  pres- 
sure of  30  lbs.  of  so  per  square  inch. 

Crank  of  cast  iron. — The  diameter  of  the  crank  pin  is  the  same 
as  for  wrought  iron,  and  also  the  length  of  the  pin.  The  diameter 
of  the  eye  for  the  crank  pin  is  two-and-one-half  times  the  diameter 
of  the  pin.  The  length  of  the  boss  at  the  shaft  equals  the  diameter 
of  the  shaft,  and  its  diameter  is  twice  the  diameter  of  the  shaft. 
The  breadth  of  the  web  at  the  crank  pin  and  journal  bosses  is 
three-fourths  of  the  diameter  of  the  respective  bosses,  and  its  thick- 
ness is  one-half  of  the  diameter  of  the  shaft,  with  a  feather  at  the 
back  tapering  from  the  large  boss  to  the  crank-pin  boss,  in  thick- 
ness one-half  of  that  of  the  web. 

Fly  wheel. — The  diameter  of  the  fly  wheel  is  generally  from  three- 
and-a-half  to  four  times  that  of  the  stroke  of  the  engine.  The 
velocity  of  the  periphery  should  always  exceed  the  velocity  of  the 


STATIONARY   ENGINES.  313 

periphery  of  the  stones  of  a  flour  or  other  mill,  to  prevent  back 
lash.  To  find  the  weight  of  the  rim  in  cwts.  multiply  the  constant 
1366  by  the  horse-power  of  the  engine,  and  divide  the  product  by 
the  mean  diameter  multiplied  by  the  number  of  revolutions  per 
minute,  and  the  quotient  is  the  weight.  To  find  the  thickness  of 
the  ring  when  the  breadth  is  given,  in  the  first  place  find  the  area 
of  the  ring  in  square  inches,  then  divide  the  weight  in  lbs.  by  the 
area  multiplied  by  '262,  and  the  quotient  is  the  thickness  in  inches. 
The  breadth  of  the  rim  for  large  wheels  is  generally  ^th  of  the 
diameter  of  the  wheel,  to  ^T^h  for  small  wheels. 

The  governor. — The  point  of  suspension  of  the  arms  should  be 
as  near  the  centre  of  rotation  as  possible,  and  the  working  angle 
should  never  exceed  45°;  the  diameter  of  the  balls  varies  from 
4  to  9  inches.  To  find  the  number  of  revolutions,  divide  375  by 
the  square  root  of  the  pendulum,  or  vertical  distance  from  the  point 
of  suspension  to  the  working  plane  of  the  centre  of  the  balls,  and 
one-half  of  the  quotient  will  be  the  number  of  revolutions  required. 
When  the  revolutions  are  given,  to  find  the  length  of  the  pendulum. 
Divide  375  by  twice  the  number  of  revolutions  per  minute,  and  the 
square  root  of  the  quotient  will  be  the  length  required ;  or  other- 
wise, divide  the  constant  187-5  by  the  square  root  of  the  pendulum, 
which  will  give  the  number  of  revolutions.  Thus,  supposing  the  ver- 
tical height  is  -^^^  inches,  the  square  root  =  6  inches,  we  have — 

— ^-i  :=  31 '25  revolutions. 

Given  the  number  of  revolutions,  to  find  the  length  of  the  pendulum 
from  the  centre  of  the  working  plane  of  the  balls  to  the  centre  of 
suspension.  Divide  i87"5  by  the  number  of  revolutions,  and  the 
square  of  the  quotient  will  be  the  length  of  the  pendulum : 

-  =  6"=  36  inches  long. 


3 1 '25 
Formulce  for  safety-valve  levers: — 

,  ,  Weight  or  pressure  on  the  valve  x  distance  of  valve  from  stud   _       .  , 
Total  length  of  lever  from  stud 

,_.  Weight  or  pressure  on  the  valve  x  distance  of  valve  from  stud        ,  ,  ,  ,       ,,     , , 

(2)  s. c „,  .  , =  total  length  of  lever. 

Weight 

/-\  Weight  on  lever  x  total  length  of  lever  from  stud        ^  ,  ,  , 

(3)  ^ isTT p — f-^^ -. =  total  pressure  on  valve. 

Distance  of  valve  from  stud 


314 


MODERN    STEAM    PRACTICE. 


This  is  when  the  valve  is  between  the  stud  or  pin  and  the  weight 
on  lever.     When  great  exactness  is  required,  subtract  the  weight 


r&--)i 


Fig.  20OB.— Safety  Valve,  with  Lever  and  Weight. 
A,  Stud.       B,  Weight.       c.  Valve. 

of  valve  and  the  effective  leverage  or  weight  of  lever  from  the  total 
(steam  lbs.)  pressure  on  the  valve.     Examples: — 

Supposing  the  pressure  of  the  steam  in  the  boiler  is  30  lbs.  per 
square  inch  above  the  pressure  of  the  atmosphere,  giving  a  total  of 
288*61  lbs.  on  the  valve — and  the  length  from  A  to  B  is  35  inches, 
and  from  A  to  C  3^  inches — we  have, 


288-6  X  3-5  _ 
AB  =  35 


weight  on  B  =  say  28 '86  lbs., 


288'6  X  •?•!;       T^  f         ,  .     , 

E  =  28-86  ~  ^^^  ^^  inches, 

-.  P^;^ — ^~  =  total  pressure  on  the  valve  =  288-6  lbs., 

which  gives  the  total  load  on  the  valve;  to  be  more  accurate,  the 
weight  of  the  valve  and  the  effective  leverage  must  be  subtracted 
from  288"6,  the  total  (steam  lbs.)  pressure  on  the  valve. 


WATER-PRESSURE   ENGINES 


In  1846  the  first  hydraulic  crane  was  erected  at  Newcastle-on- 
Tyne,  for  discharging  ships,  the  supply  of  water  being  pbtained 
from  the  mains  connected  with  the  town  service  reservoirs.  After- 
wards one  was  erected  at  Liverpool,  and  another  at  the  new  dock 
at  Grimsby.  The  Liverpool  crane,  like  the  Newcastle  one,  was 
supplied  with  water  from  the  town  mains ;  but  at  Grimsby  a  tower 
was  built  with  a  tank  into  which  the  water  was  pumped  by  a  steam 
engine.     In  the  former  cases  the  irregularity  of  pressure  consequent 


STATIONARY   ENGINES.  3 15 

on  the  varying  drain  upon  the  pipes  for  the  ordinary  consumption 
proved  a  serious  disadvantage;  but  this  drawback  was  not  experi- 
enced at  Grimsby,  where  the  tank  upon  the  tower  furnished  an 
uninterrupted  supply.  In  the  absence  of  a  natural  head  of  water, 
with  pipes  laid  for  conveying  it  to  a  lower  situation,  the  erection  of 
water  towers  was  a  serious  obstacle  in  extending  the  principle  of 
the  hydraulic  crane,  and  engineering  ingenuity  resorted  to  another 
form  of  head,  which  possesses  the  advantages  of  being  applicable 
at  a  moderate  cost  in  nearly  all  situations,  and  of  lessening  the 
size  of  the  pipes  and  cylinders  by  affording  a  pressure  of  greatly 
increased  intensity.  The  apparatus  by  which  this  is  effected  has 
been  named  the  "accumulator,"  because  of  its  accumulating  the 
power  exerted  by  the  engine  in  charging  it.  The  accumulator  is 
in  fact  a  reservoir  giving  pressure  by  load  instead  of  by  elevation, 
and  its  use  is  to  equalize  the  duty  of  the  engine  in  cases  where  the 
quantity  of  power  to  be  supplied  is  subject  to  great  and  sudden 
fluctuations.  In  the  application  of  water-pressure  machinery,  where 
an  artificial  head  of  water  has  to  be  obtained,  the  real  source  of 
power  is  the  steam  engine  employed  in  pumping  the  water  into  the 
accumulator,  and  the  water  acts  simply  as  a  convenient  means  of 
storing  up  the  power  of  the  engine,  and  applying  it  whenever 
wanted  at  the  distant  points  where  the  work  has  to  be  done.  We 
may  take  as  an  example  of  this  the  Victoria  Docks  in  London, 
where  the  area  over  which  the  power  is  extended  is  so  great  as  to 
require  4  miles'  length  of  mains  to  convey  the  water  to  the  several 
cranes,  hoists,  and  to  the  lock-gates. 

In  Hastie's  variable  water-power  engine  the  quantity  of  water  is 
regulated  to  the  work  done  automatically.  There  are  two  or  more 
oscillating  cylinders  rocking  on  trunnions  at  their  lower  ends,  the 
pistons  being  solid  plungers,  and  centered  on  a  crank  pin  which  is 
free  to  move  in  a  slide,  so  that  the  throw  becomes  variable  according 
to  the  demand  on  the  engine. 

THE   ACCUMULATOR. 

The  accumulator  consists  of  a  large  cast-iron  cylinder  A  (Fig.  201)^ 
fitted  with  a  plunger  B,  from  which  a  loaded  case  C  is  suspended  to 
give  pressure  to  the  water  injected  by  the  engine.  The  load  upon  the 
plunger  B  is  usually  such  as  to  produce  a  pressure  in  the  cylinder 
equal  to  a  column  of  water  1500  feet  in  height,  and  the  cyHnder  is 


3i6 


MODERN   STEAM    PRACTICE. 


made  large  enough  to  contain  the  quantity  of  water  which  can  be 
required  from  it  at  once  by  the  simultaneous  action  of  all  the 
hydraulic  machines  connected  with  it.  If,  how- 
ever, the  engine  pumps  more  water  into  the 
accumulator  than  the  hydraulic  machines  re- 
quire, the  plunger  rises  and  makes  room  in  the 
cylinder  for  the  surplus ;  and  when,  on  the  other 
hand,  the  supply  from  the  engine  is  less  than 
the  quantity  required,  the  plunger  with  its  load 
descends  and  makes  up  the  deficiency  out  of 
the  store.  The  accumulator  serves  also  as  a 
regulator  to  the  engine,  for  when  the  plunger 
rises  to  a  certain  height  it  begins  to  close  the 
throttle  valve  in  the  steam  pipe,  so  as  gradually 
to  reduce  the  speed  of  the  engine,  until  the 
descent  of  the  plunger  again  requires  an  increase 
of  power.  The  introduction  of  the  accumulator 
removed  all  the  obstacles  to  the  extension  of 
water-pressure  machinery,  which  has  been  now 
practically  tested  in  nearly  all  the  principal 
docks  and  in  many  of  the  government  establish- 
ments in  this  country.  This  class  of  machinery 
Fig.  20I.— Vertical  Section  of  has  also  bccn  adoptcd  in  many  of  the  principal 
Accumuiator.-A,  Cylinder,    railway  statious,  not  Only  for  cranage,  but  also 

B,  Plunger,    c.  Loaded  case.  -'  '  ■^  "    ' 

for  working  turntables,  traversing  machines, 
waggon-lifts,  hauling  machines,  &c.  It  is  also  extensively  used  for 
raising  and  tipping  waggons  in  the  shipment  of  coal,  for  opening 
and  closing  bridges,  and  for  many  other  purposes. 


PUMPING  ENGINE   FOR   CHARGING   THE   ACCUMULATOR. 


The  most  approved  form  of  the  pumping  engine  for  charging 
the  accumulator  is  that  of  two  high-pressure  cylinders  fixed  hori- 
zontally, with  double-acting  pumps  directly  connected  with  the 
piston  rods;  the  form  of  pump  being  the  solid  bucket  and  plunger 
system.  In  the  arrangement  shown  (Fig.  202)  the  OUT  stroke  of  the 
pump  forces  the  water  contained  in  the  annular  space  surrounding 
the  plunger  E  into  the  accumulator,  while  a  further  supply  of  water 
enters  behind  the  piston  F  through  the  suction  valve  G.  In  the 
IN  stroke  the  water  behind  the  piston  is  discharged  through  the 


STATIONARY   ENGINES. 


317 


delivery  valve  D,  half  of  it  passing  round  into  the  annular  space  on 
the  other  side  of  the  piston,  the  remaining  half  being  forced  into 
the  accumulator.  As  the  area  of  the  plunger  E  is  exactly  half  that 
of  the  piston  F,  each  stroke  of  the  pump  delivers  the  same  quantity 
of  water  into  the  accumulator.  Much  difficulty  has  been  experi- 
enced to  secure  proper  joints  for  the  pipes  of  hydraulic  machinery; 
no  plan  appears  to  stand  so  well  as  a  small  ring  of  gutta  percha 


TaintottJ. 


Fig.  202. — Longitudinal  Section  of  Force  Pump. 
D,  Delivery  valve.     E,  Plunger.     F,  Piston.     G,  Suction  valve,     j,  Gutta-percha  ring  joint. 

compressed  into  a  recess  formed  on  the  end  of  one  pipe,  with  a 
projection  on  the  adjoining  pipe  accurately  turned  to  fit  the  recess, 
like  a  spigot  and  faucet. 

Rivetting,  both  of  boilers,  girders,  and  shipwork,  is  now  in  many 
cases  carried  out  by  hydraulic  pressure  through  the  action  of 
accumulators,  loaded  as  high  in  some  cases  as  1500  lbs.  per  square 
inch,  India  rubber  or  flexibly  jointed  metal  pipes  being  used  to 
convey  the  water  to  the  working  parts. 

WATER   WHEELS. 

Water  wheels  may  be  classed  as  vertical  and  horizontal,  of 
these  the  vertical  class  may  be  subdivided  into  undershot,  overshot, 
and  breast  wheels,  whilst  the  turbine  form  represents  the  horizontal 
class.  The  undershot  wheel  is  simply  the  old  form  of  water  wheel, 
made  of  wood,  with  radial  float-boards,  on  which  the  water 
presses  as  it  flows  past.  The  efficiency  or  ratio  of  the  useful  to  the 
total  work  is  small  in  such  wheels,  being  only  about  ^.  In  the  over- 
shot or  breast  wheel  the  water  is  led  on  at  or  near  the  top,  and  the 
floats  are  made  of  a  bucket  form;  the  weight  of  the  water  is  in 
this  manner  taken  advantage  of  as  well  as  the  impulse  due  to  velo- 
city.    The  efficiency  of  such  wheels  is  about  ^  to  f. 

The  turbine  form  of  wheel  is  very  suitable  for  high  falls  where  a 
great  velocity  of  flow  can  be  obtained,  and  is  not  aff"ected  by  "back- 


3l8  MODERN    STEAM   PRACTICE. 

water  "  as  the  vertical  wheels  are.  There  are  several  forms  of  such 
wheels,  depending  upon  the  direction  in  which  the  water  is  allowed 
to  impinge  upon  the  vanes  or  blades.  These  vanes  are  curved,  and 
it  is  of  importance  that  the  water  should  be  directed  upon  them  in 
such  a  manner  as  to  cause  as  little  shock  as  possible  ;  the  propelling 
action  being  due  to  the  pressure  and  reaction  on  the  vane  due  to  the 
gliding  of  the  water  along  its  surface.  Curved  vanes  are  found  in 
this  manner  to  be  more  efficient  than  flat  surfaces,  their  surfaces 
being  in  the  direction  of  the  resultant  of  the  lines  of  motion  of  the 
jet  and  vane.  Turbines  are  now  largely  used  on  natural  falls, 
notably  so  in  America  and  in  France  and  Switzerland. 

HYDRAULIC   CRANE. 

Of  the  various  applications  of  water  pressure,  the  most  com- 
mon is  that  of  a  hydraulic  press  with  a  set  of  sheaves  used  in  the 
inverted  order  of  blocks  and  pulleys,  with  the  object  of  obtaining 
an  extended  motion  in  the  chain  from  a  comparatively  short  stroke 
of  piston.  The  general  arrangement  of  the  machinery  for  working 
such  a  crane  may  be  described  as  follows : — The  pressure  cylinder  A 
(Fig.  203)  is  fiixed  horizontally  below  the  surface  of  the  ground  in  a 
chamber  at  the  foot  of  the  crane,  and  is  fitted  with  the  ram  B,  carry- 
ing the  pulleys  C  at  its  outer  extremity.  The  lifting  chain  is  made 
fast  at  one  end  to  the  cylinder  A,  and  passes  alternately  round  the 
movable  pulleys  C  and  the  pulleys  D  at  the  inner  end  of  the  cylinder; 
and  is  then  led  round  the  guide  pulley  E  up  to  the  crane  post  F, 
and  along  the  jib  to  the  load.  The  motion  of  the  lifting  chain  is  con- 
trolled by  means  of  the  handle  G,  acting  upon  the  inlet  and  outlet 
valves,  which  are  kept  closed  by  the  weights  H  and  I ;  by  opening 
the  inlet  valve  H  (Fig.  204)  the  water  is  let  into  the  cylinder  A  from 
the  pressure  pipe  J,  and  acting  on  the  plunger  raises  the  load ;  by 
opening  the  outlet  valve  I  the  water  escapes  from  the  cylinder  into 
the  exhaust  pipe  K,  allowing  the  load  to  descend.  The  travel  of 
the  ram  B  in  the  outward  stroke  is  prevented  from  exceeding  the 
proper  limit  by  the  pulley  block  C  coming  in  contact  with  a  stop 
connected  with  the  handle  G,  which  closes  the  inlet  valve  H,  and 
prevents  the  load  from  being  lifted  too  high.  The  return  stroke  of 
the  ram  is  effected  by  the  load  suspended  from  the  chain ;  and  in 
the  absence  of  any  load,  a  small  supplementary  ram  L  is  employed 
to  force  the  main  ram  B  back,  the  slack  chain  being  made  to  run 
out  by  the  permanent  weight  M. 


STATIONARY  ENGINES. 


319 


'^p^^W^X     ' ' 

Fig.  203. — Hydraulic  Crane.     General  Arrangement  of  Machinery. 
A,  Pressure  cylinder.     B,  Ram.     c  and  D,  Pulleys.     E,  Guide  pulley.     F,  Crane  post.     G,  Handle 
for  valves.       h  and  i,  Weights.       j,  Pressure  pipe.       K,  Exhaust  pipe.      L,  Supplementary 
valve.      M,  Permanent  weight.      N  o,  Cylinders  and  plungers  for  turning  the  crane. 


Fig.  204.— Cylinder  and  Valves  for  Double-power  Hydraulic  Crane. 

A,  Cylinder.     B,  Ram.     c  and  D,  Pulleys.     E,  Piston.     F,  Valve  chest.     H,  Inlet  valve.     I,  Outlet  valve. 

J,  Pressure  pipe.     K,  Exhaust  pipe.     L,  Valve  for  higher  power.     M,  Valve,     n.  Relief  valve. 


320 


MODERN   STEAM   PRACTICE. 


To  meet  the  variation  of  load  it  was  formerly  the  practice  to 
combine  three  of  the  pressure  cylinders  so  as  to  act  either  sepa- 
rately or  collectively  upon  the  lifting  chain ;  but  a  variation  of  power 
is  now  obtained  with  a  single-bored  cylinder,  fitted  with  a  combined 
piston  and  ram,  as  follows:— A  (Fig.  204)  is  the  cylinder,  fitted  with 
the  piston  E  and  ram  B ;  the  water  from  the  accumulator  enters  the 
valve  chest  F  through  the  pressure  pipe  J  and  the  inlet  valve  H. 
For  the  lower  power  the  water  is  admitted  to  both  sides  of  the 
piston  E  by  opening  the  valve  L,  in  which  case  the  power  exerted 
and  the  water  exoended  are  proportionate  to  the  area  of  the  ram  B. 

For  the  higher  power  the  valve  L  is 
closed  and  the  valve  M  opened,  so 
that  the  front  side  of  the  piston  E  is 
thrown  open  to  the  exhaust  K,  and 
the  result,  both  as  regards  power 
and  expenditure,  is  then  propor- 
tionate to  the  full  area  of  the  pis- 
<•,, ,     r   o  r  J     rx^   v,     tou  E.     It  is  scldom  necessary  to 

Fig.  205. — Deta..  of  Valves  for  Cylinder  of  Double-  ■' 

power   Hydraulic    Crane.  —  F,  Valve   chest.       haVC     morC     than    thcSC     loWCr    and 
H,  Inlet  valve,     i.  Outlet  valve.      L,  Valve  for      .   .     ,  t.     j.         1_  j.t,  •    j 

higher  power.  M,  Valve.  N,  Relief  valve.        higher  powcrs ;  but  whcrc  a  third 

or  less  power  is  required,  a  smaller 
ram  is  used  with  the  other.  For  lowering  the  load  the  valves  H  and 
M  are  closed  and  the  outlet  valve  I  opened,  allowing  the  water  to 
escape  from  the  cylinder  A  into  the  exhaust  pipe  K ;  at  the  same 
time  the  valve  L  is  opened  to  allow  the  water  to  follow  up  the  piston 

in  the  inward  stroke.  The  packing  of 
the  solid  piston  A  is  held  in  position  by 
means  of  a  ring  of  metal  B,  and  secured  to 
the  piston  by  stud  bolts  and  nuts,  and 
consists  of  a  cupped  leather  washer  C, 
,    „.         J  ^      J  T     t.     which  is  pressed  against  the  side  of  the 

Fig.  206. — Piston  and  Cupped  Leather  '^  " 

for  Cylinder  of  Double-power  Hy-  Cylinder  by  thc  hydraulic  prcssurc. 

draulic  Crane. — A,  Piston.     B,  Ring  _      ,        ,  ,.  ■,  .  T     j 

with  bolts,   c,  Cupped  leather.  In  hydraulic  cranes  the  power  is  applied 

not  only  for  lifting  the  load,  but  also 
for  swinging  the  jib,  which  is  effected  by  means  of  a  rack  or  chain 
acting  on  the  base  of  the  movable  part  of  the  crane,  connected 
either  with  a  cylinder  and  piston,  or  with  two  single-acting  cylinders 
applied  to  produce  the  same  effect  by  alternate  action ;  as  shown, 
the  two  cylinders  N  and  O  (Fig.  203)  are  fitted  with  rams,  working 
by  a  chain  passing  round  the  base  of  the  crane  post  F.     The  motion 


STATIONARY   ENGINES.  321 

is  controlled  by  means  of  a  slide  valve  worked  by  a  handle  situated 
alongside  the  handle  G,  so  that  while  the  water  is  admitted  to  one 
cylinder  the  other  is  open  to  the  exhaust.  The  travel  of  the  rams 
is  limited  by  means  of  a  .tappet  rod  connected  with  the  handle  of 
the  slide  valve,  whereby  the  crane  is  prevented  from  being  turned 
round  too  far.  Small  hydraulic  rotary  engines  have  been  intro- 
duced for  working  cranes,  and  in  many  cases  they  can  be  easily 
attached  to  existing  hand  cranes. 

The  absence  of  any  sensible  elasticity  in  water  renders  the  motions 
resulting  from  its  pressure  capable  of  the  most  perfect  control  by 
means  of  the  valves  which  regulate  the  inlet  and  outlet  passages ; 
but  this  property,  which  gives  so  much  certainty  of  action,  tends  to 
cause  shocks  and  strains  to  the  machinery  by  suddenly  resisting 
the  momentum  acquired  by  the  moving  parts.  Take,  for  example, 
the  case  of  a  hydraulic  crane  swinging  round  with  a  load  suspended 
fromx  the  jib:  the  motion  being  produced  by  the  water  entering 
into  one  cylinder  and  escaping  from  the  other,  it  is  obvious  that  if 
the  water  passages  be  suddenly  closed,  the  ram,  impelled  forward 
by  the  momentum  of  the  loaded  jib,  but  met  by  an  unyielding  body 
of  water  deprived  of  outlet,  would  be  brought  to  rest  so  abruptly 
as  to  cause  in  all  probability  some  damage  to  the  machine.  So 
also,  in  lowering  a  heavy  weight,  if  the  escape  passages  were  too 
suddenly  closed,  a  similar  risk  of  injury  would  arise  from  the  sudden 
stoppage  of  the  weight.  But  these  liabilities  to  injury  are  effectually 
removed,  in  the  case  of  a  single-acting  cylinder,  by  fitting  a  relief 
valve  in  connection  with  the  water  passages,  consisting  of  a  small 
clack  valve  N  opening  upwards  against  the  effective  pressure,  so  as 
to  permit  the  pent-up  water  in  the  cylinder  to  be  forced  back  into 
the  pressure  pipe,  whenever  it  becomes  subject  to  a  compressive 
force  exceeding  the  pressure  given  by  the  accumulator;  and  in 
the  case  of  a  double-acting  cylinder  fitted  with  a  piston  and  slide 
valve,  or  where  two  single-acting  cylinders  with  rams  working 
alternately  are  controlled  by  a  slide  valve — as  in  the  instance  of  the 
cylinders  N  and  O — for  turning  the  crane,  relief  valves  are  fitted  in 
connection  with  the  slide  valve.  These  consist  of  four  small  leather 
flap  valves  (Fig.  207),  with  metal  pieces  at  the  top  and  bottom.  The 
passages  PP  communicate  with  the  pressure  pipe  j,  and  the  pas- 
sages E  E  with  the  exhaust  K.  When  the  slide  valve  is  moved  in 
the  direction  of  the  arrow  the  pressure  is  first  cut  off  from  the 

port  R  by  the  top  of  the  valve,  the  port  S  being  still  open  to  the 

21 


322 


MODERN    STEAM   PRACTICE. 


exhaust  K;  at  the  same  instant  the  flap  valve  T  opens  upwards 
and  allows  a  small  quantity  of  water  to  pass 
from  the  exhaust  K  into  the  port  R  to  follow 
up  the  ram  until  brought  to  rest.  When 
the  slide  valve  arrives  at  the  central  position 
as  shown,  the  port  S  is  closed  to  the  exhaust, 
and  the  pressure  in  it  being  increased  by 
the  further  motion  of  the  ram  before  it  is 
completely  stopped,  the  second  flap  V  is 
raised,  and  a  small  quantity  of  water  forced 
back  into  the  passage  P  communicating  with 
the  pressure  pipe  J.  When  the  slide  valve 
is  moved  in  the  opposite  direction,  the  two 

Fig.  207.— Section  of  Slide  Valve  &  remaining  relief  valvcs  are  brought  into  ac- 

Relief  Valves  for  Hydraulic  Crane. 

„  ,       ■  13  tion  in  the  same  manner.     By  these  means 

E  E,  Exhaust  pa.ssages.    j,  Pressure  -' 

pipe.   K,  Exhaust,  p  p,  Pressure  a.11  risk  of  coucussion  is  avoidcd,  aud  per- 

passages.     R  and  s.  Ports.  ,  ,  ...  1   •         1 

feet  control  over  the  machme  is  combmed 
with  great  softness  of  action. 


DOCK  GATES. 


The  method  generally  adopted  for  opening  and  closing  dock 
gates  by  means  of  hydraulic  pressure  consists  in  applying  to  each 
gate  a  pair  of  cylinders  with  rams  and  multiplying  sheaves,  similar 
to  those  used  for  the  hoisting  apparatus  in  hydraulic  cranes.  One 
of  these  cylinders  opens  the  gate  and  the  other  closes  it;  and  the 
whole  of  the  machinery  is  placed  in  chambers  beneath  the  ground. 
The  water  is  admitted  from  the  pressure  pipe  J  to  the  cylinder  A 
(Fig.  208)  through  the  inlet  valve  H  by  means  of  the  handle  G ;  the 
same  motion  of  the  handle  also  opens  the  outlet  valve  of  the  other 
cylinder  B.  The  opposite  motion  of  the  handle  G  opens  the  outlet 
valve  I,  allowing  the  water  to  escape  from  the  cylinder  A  into  the 
exhaust  pipe  K,  and  at  the  same  time  admits  the  pressure  to  the 
cylinder  B.  A  stop  M  connected  with  the  handle  G  prevents  the 
ram  from  travelling  too  far  in  the  out  stroke,  by  closing  the  inlet 
>'alve;  and  the  return  stroke  of  the  ram  is  effected  by  means 
of  the  weight  L.  This  arrangement  has  been  applied  to  several 
of  the  London  and  Liverpool  Docks,  as  well  as  to  some  others 
throughout  the  country. 

In  Fig.  209  we  give  an  engraving  of  the  general  plan  of  a 


STATIONARY   ENGINES,  S^S 

dock  entrance  which  has   been   adopted  in  some  instances,   and 


4J        •     *■ 

(3 


e  % 


found  to  answer  extremely  well.    Instead  of  connecting  the  hauling 
cylinders  with  each  gate,  a  line  of  shafting  A,  driven  by  a  small 


324 


MODERN   STEAM   PRACTICE. 


water-pressure  engine  B,  is  laid  beneath  the  surface  of  the  ground, 
parallel  with  the  coping  on  each  side  of  the  entrance,  and  by  means 
of  clutches  is  thrown  into  or  out  of  gear  with  each  gate  crab.     A 


J'retSSure' 


Fig.   209.  —  Arrangement  for  Lock-gate   Machinery. 
A,  Shafting.     B  B,  Pressure  engines,     c  c,  Capstans. 

wire  from  the  engine  extends  the  whole  length  of  the  snafting,  so 
that  the  engine  can  be  regulated  from  the  point  where  the  work 
has  to  be  done.  A  more  recent  method  is  to  attach  a  separate 
engine  to  each  crab,  and  also  to  the  sluices;  and  in  some  instances 
these  engines  have  been  fitted  to  existing  machines  without  inter- 
rupting the  traffic.     The  rapidity  with  which  dock  gates  can  be 


STATIONARY   ENGINES.  325 

Opened  and  closed  by  these  appliances  is  limited  only  by  consider- 
ations of  safety  to  the  gates,  the  time  taken  in  actual  practice 
being  about  two  minutes.  In  nearly  all  the  cases  in  which  hydraulic 
pressure  has  been  applied  for  the  moving  of  dock  gates,  it  is  also 
used  for  opening  and  closing  the  levelling  shuttles,  and  in  many 
cases  also  for  working  the  capstans.  The  former  purpose  is  effected 
by  the  direct  application  of  a  cylinder  and  piston  fixed  above  the 
shuttle:  and  the  latter  is  accomplished  by  throwing  the  capstan  c 
into  gear  with  the  shafting  A. 

WATER-PRESSURE   ENGINES   FOR  DOCK   GATES,   &c. 

These  engines  consist  of  a  combination  of  three  oscillating  cylin- 
ders, working  cranks  inclined  120°  to  one  another.  The  cylinders  A 
(Fig.  2 10)  are  fitted  with  plungers  B,  instead  of  pistons,  and  are  there- 
fore only  single-acting.  The  slide  valves  V  are  worked  by  the  oscil- 
lation of  the  cylinders,  communicated  through  the  levers  L.  When 
the  back  end  of  the  cylinder  is  depressed,  the  slide  valve  is  lowered, 
and  allows  the  water  to  enter  from  the  pressure  pipe  P  through  the 
pipe  C  to  the  cylinder,  where  it  acts  upon  the  plunger  in  the  out 
stroke;  and  in  the  return  stroke  the  back  end  of  the  cylinder  is  raised, 
the  cylinder  port  C  is  closed  to  the  pressure  pipe  P,  and  open  to 
the  exhaust  E.  A  small  relief  valve  is  fitted  to  the  cylinder  pipe  C, 
opening  against  the  pressure,  which  prevents  any  shock  when  the 
communication  with  the  exhaust  is  closed  at  the  end  of  the  return 
stroke.  These  engines  have  occasionally  been  made  with  pistons, 
so  as  to  be  double-acting;  but  for  the  great  pressures  employed 
where  accumulators  are  used,  the  single-acting  arrangement  with 
plunger  is  preferred.  It  will  be  observed  that  with  the  arrange- 
ment of  cranks  dividing  the  path  into  three  equal  parts,  there  is  no 
liability  of  the  engine  stopping  on  the  "dead  centre,"  as  it  is  termed, 
the  one  crank  assisting  the  other  over  the  extreme  points. 

In  working  swing  bridges  by  means  of  water  pressure,  a  central 
press  is  generally  applied  to  lift  the  entire  bridge  clear  of  its 
supports,  and  it  is  then  turned  by  an  application  similar  to  that 
used  for  swinging  a  crane.  An  example  of  a  swing  bridge  on  this 
principle  is  seen  at  Wisbech,  having  an  opening  of  85  feet,  arranged 
for  a  double  roadway  in  one  leaf,  weighing  about  450  tons.  The 
power  is  derived  from  an  accumulator  charged  by  a  hand  force 
pump,  and  notwithstanding  its  great  length  and  weight  the  bridge 


326 


MODERN   STEAM   PRACTICE. 


fSecUoruiZ'  jELevatLcny. 


Fig.  2IO. — Water-pressure  Engine. 

A  A,  Cylinders,     b  b.  Plungers,    c,  Pipe  to  cylinder,     e,  Exhaust  pipe.     L,  Lever  for  working  slide 
valve,     p.  Pressure  nine,     v.  Slide  valve. 


STATIONARY   ENGINES.  32/ 

can  be  lifted  and  turned  in  less  than  two  minutes.  The  plan  of 
using  an  accumulator  charged  in  this  way  has  been  adopted  for  a 
railway  drawbridge  near  Caermarthen;  and  it  can  be  applied  to 
many  other  purposes  requiring  a  concentrated  exertion  of  power 
with  intervening  periods  of  inaction. 

One  application  of  water  pressure  with  an  accumulator,  for  the 
purpose  of  rapidly  lifting  or  lowering  heavy  loads,  calls  for  special 
notice  because  of  its  growing  importance.  We  refer  to  vertical 
hoists  at  the  landing  stations  of  steam  ferries,  where  the  traffic  of  a 
railway  is  required  to  be  passed  over  a  river  or  estuary  not  spanned 
by  a  bridge.  The  traffic  of  the  Aix-la-Chapelle,  Diisseldorf,  and 
Ruhrort  Railway  is  by  this  means  shipped  and  unshipped  at  the 
ferry  across  the  Rhine ;  and  such  is  the  rapidity  and  facility  of  the 
operation  that  a  train  of  twelve  coal  waggons,  weighing  collectively 
133  tons,  can  be  transferred  from  the  deck  of  the  steamer  to  the 
railway,  a  height  of  about  20  feet,  in  twelve  minutes.  Each  hoist 
lifts  two  waggons  at  a  time,  and  raises  its  load  in  ten  or  twelve 
seconds.  These  hoists  are  so  arranged  as  always  to  accommodate 
themselves  to  the  level  of  the  boat,  and  also  to  stop  at  the  exact 
level  of  the  railway. 

WATER   POWER   FROM   NATURAL   FALLS. 

Having  said  this  much  on  that  branch  of  the  subject  which 
embraces  the  two  principles  of  accumulation  and  transmission  of 
water  power,  we  will  now  notice  the  applications  of  water  pressure 
as  derived  from  natural  falls.  When  the  moving  power  consists  of 
a  natural  column  of  water,  the  pressure  rarely  exceeds  250  or  300 
feet;  and  in  such  cases,  to  produce  rotary  motion,  a  pair  of  cylin- 
ders and  pistons  are  employed,  with  slide  valves  resembling  in  some 
measure  those  of  a  high-pressure  engine,  but  having  relief  valves 
to  prevent  shock  at  the  return  of  the  stroke.  Where  the  engine  is 
single-acting,  with  plungers  instead  of  pistons,  as  in  the  water- 
pressure  engine  already  described,  the  relief  valves  are  greatly 
simplified,  and  indeed  are  reduced  to  a  single  clack  in  connection 
with  each  cylinder,  opening  against  the  pressure,  as  the  relief  valve 
in  the  valve  chest  of  the  hydraulic  crane.  The  water  engines 
erected  at  the  lead  mines  at  Allenheads,  in  Northumberland,  pre- 
sent an  example  of  the  utilization  of  natural  falls  in  this  country. 
These  engines  are  used  for  the  various  purposes  of  crushing  ore, 


328  MODERN    STEAM   PRACTICE. 

raising  materials  from  the  mines,  pumping  water,  giving  motion  to 
machinery  for  washing  and  separating  the  ores,  and  driving  a  saw- 
mill and  the  machinery  of  a  workshop.  Small  streams  of  water, 
which  flowed  down  the  steep  slopes  of  adjoining  hills,  have  been 
collected  into  reservoirs  at  elevations  of  about  200  feet,  and  pipes 
have  been  laid  from  them  to  the  engines.  Water-pressure  machin- 
ery is  invaluable  in  such  a  hilly  district,  where  steam  power  is 
almost  impracticable  in  a  commercial  point  of  view,  from  the  great 
cost  of  conveying  coals  to  the  works. 

An  application  of  hydraulic  machinery  in  situations  where  falls 
of  sufficient  altitude  for  working  water-pressure  engines  cannot 
be  obtained  has  been  carried  out  at  these  mines,  which  deserves 
special  notice.  For  the  purpose  of  draining  an  extensive  dis- 
trict, and  searching  for  new  veins,  a  drift  way  or  open  level  nearly 
6  miles  in  length  was  cut.  This  drift  way  runs  beneath  the 
valley  of  the  Allen,  nearly  in  the  line  of  that  river,  and  upon 
its  course  three  mining  establishments  have  been  erected.  At 
each  of  these  power  was  required  for  the  various  purposes  already 
mentioned,  and  it  was  desirable  to  obtain  this  power  without  re- 
sorting to  steam  engines.  The  river  Allen  was  the  only  resource, 
but  its  descent  was  not  sufficiently  rapid  to  permit  of  its  being 
advantageously  applied  to  water -pressure  engines;  it  abounded, 
however,  with  falls  suitable  for  overshot  wheels,  and  it  was  deter- 
mined to  employ  the  stream,  by  means  of  such  wheels,  in  forcing 
water  into  accumulators,  and  then  transmitting  by  pipes  the  power 
thus  stored  to  the  numerous  points  where  it  was  required.  In  this 
arrangement  intensity  of  pressure  takes  the  place  of  magnitude  of 
volume,  and  the  power  derived  from  the  stream  assumes  a  form 
susceptible  of  unlimited  distribution  and  division,  and  capable  of 
being  utilized  by  small  and  compact  machines. 

A  somewhat  similar  plan  is  also  adopted  at  the  coaling  establish- 
ment for  the  navy  at  Portland  Harbour.  The  object  in  this  case 
is  to  provide  power  for  working  hydraulic  cranes  and  hauling 
machines  for  coaling  war  steamers.  A  reservoir  on  an  adjoining 
height  affords  an  available  head  of  upwards  of  300  feet;  but  in 
order  to  diminish  the  size  of  the  pipes,  cylinders,  and  valves  con- 
nected with  the  machinery,  and  also  to  obtain  greater  rapidity  of 
action,  a  hydraulic  pumping  engine  and  accumulator  are  interposed, 
so  as  to  intensify  the  pressure  and  diminish  the  volume  of  water 
acting-  as  a  medium  of  transmission. 


STATIONARY   ENGINES.  329 

HYDRAULIC   MACHINERY   FOR   WAREHOUSING   GRAIN 
AT   THE   LIVERPOOL   DOCKS. 

The  dock  around  which  the  blocks  of  warehouses  on  the  Liverpool 
side  of  the  river  are  situated,  shown  in  the  general  plan  Fig.  211, 
is  570  feet  long,  230  feet  broad  at  one  end,  and  180  feet  at  the  other. 
Three  sides  of  it  are  occupied  by  separate  blocks  of  warehouses, 
connected  by  wrought-iron  bridges.  The  blocks  on  the  east  and 
west  sides  are  650  feet  long  and  70  feet  wide,  and  that  on  the  north 
ehd  is  the  same  width  and  185  feet  long.  Each  block  contains  five 
stories,  as  shown  in  the  transverse  section.  Fig.  215;  above  the  fifth 
or  top  storage  floor,  and  partly  in  the  roof,  is  placed  the  machinery 
floor;  and  below  the  quay  level  are  wells  and  arched  subways  for 
the  reception  of  the  underground  ,  machinery.  There  are  five  dis- 
charging berths  for  large  vessels,  one  at  the  north  block  and  two 
each  at  the  east  and  west  blocks;  and  additional  accommodation  is 
provided  for  small  vessels.  In  the  centre  or  north  block  is  placed 
the  steam  engine  A,  of  370  horse-power,  which  in  addition  to 
driving  the  whole  of  the  machinery  in  the  warehouses,  supplies 
power  for  working  the  lock  machinery  and  the  bridges.  These 
consist  of  two  bridges  of  60  feet  span  and  one  of  50  feet,  twelve 
sluices,  ten  powerful  ship  capstans,  and  twenty-four  machines  for 
opening  and  closing  the  lock  gates. 

The  principal  processes  required  to  be  performed  by  the  machin- 
ery in  the  warehouses  are: — -Discharging  grain  in  bulk  direct  on  to 
the  quay  or  into  the  warehouses; — hoisting  grain  in  bags  or  casks 
on  to  the  quay; — discharging  ordinary  merchandise  direct  on  to 
the  quay  or  on  to  any  floor  in  the  warehouses,  and  loading  out- 
ward-bound vessels; — lifting  and  lowering  sacks  or  other  merchan- 
dise on  platform  elevators  and  jiggers,  to  or  from  any  floor; — 
elevating,  screening,  weighing,  and  distributing  grain  in  bulk,  and 
conveying  it  to  and  from  all  parts  of  the  warehouses,  and  outwards 
for  delivery  into  ships  or  waggons; — and  transferring  grain  from 
one  part  of  the  warehouses  to  any  other  part. 

The  two  accumulators  which  generate  the  water  pressure  employed 
as  the  medium  for  conveying  power  to  the  machinery  are  situated 
at  CC  in  the  general  plan  Fig.  211,  at  each  end  of  the  centre  or 
north  block  of  building ;  and  between  the  west  block  and  the  river 
entrances  a  large  auxiliary  accumulator  is  placed.  The  two  accum- 
ulators in  the  north  block  are  each  weighted  with  a  load  of  70  tons, 


330 


MODERN   STEAM    PRACTICE. 


acting  on  a  ram   17  inches  in  diameter,  with  a  vertical  range  of  17 
feet;  and  the  auxihary  accumulator  is  loaded  with  100  tons,  acting 


Fig.  211. — General  Plan  of  Warehouse. 
A,  Steam  engine.        b,  Boilers.        c  c,  Accumulators. 

on  a  20-inch  ram  having  a  range  of  23  feet.     The  water  pressure  is 
conducted  through  cast-iron  main  pipes,  varying  from  6  inches  to 


STATIONARY   ENGINES.  331 

3  inches  in  diameter,  and  wrought- iron  branch  pipes  convey  it 
from  the  mains  to  the  several  machines.  In  order  to  economize 
the  consumption  of  water,  which  is  obtained  from  the  town  supply, 
return  pipes  are  laid  to  conduct  the  exhaust  water  from  all  the 
machines  back  again  into  a  well  in  the  engine  house,  from  which 
the  pumps  draw  their  supply;  and  thus  the  same  water  is  used  over 
and  over  again.  The  steam  engine  for  supplying  the  accumulators 
is  situated  on  the  quay  level  at  A,  with  its  boilers  at  B;  it  is  a  hori- 
zontal high -pressure  engine  with  two  steam  cylinders,  and  the 
plungers  of  the  double-acting  force  pump  are  attached  directly  to 
the  piston  rod.  The  engine  is  made  in  duplicate  in  all  its  parts, 
to  admit  of  either  side  being  worked  separately  in  case  of  need. 
Double-acting  lift  pumps  are  provided  for  raising  the  supply  and 
the  return  water  from  the  storage  well  into  a  settling  tank  above 
the  level  of  the  engine,  from  which  the  forcing  pumps  draw  their 
water.  The  engine  is  capable  of  forcing  209,350  cubic  feet  of  water 
per  minute  against  the  accumulator  pressure  of  700  lbs.  per  square 
inch. 

A  number  of  experiments  were  made  for  the  purpose  of  ascer- 
taining the  best  means  of  conveying  the  grain  horizontally  from 
one  part  of  the  warehouses  to  another.  The  common  method  by 
means  of  revolving  screws  was  first  tried,  the  experiments  being 
conducted  at  a  brewery  fitted  up  with  this  class  of  machinery. 
The  screw  employed  was  12  inches  diameter  and  4  inches  pitch, 
made  in  lengths  of  about  12  feet  from  bearing  to  bearing;  the 
space  between  the  screw  and  the  fixed  casing  in  which  it  revolved 
was  %  inch.  At  sixty  revolutions  per  minute,  which  was  found  to 
be  the  maximum  effective  speed,  this  screw  discharged  the  grain  at 
the  rate  of  6^  tons  per  hour,  and  required  a  power  of  0*04  horse- 
power for  every  foot  run.  The  sectional  area  of  the  body  of  grain 
propelled  was  49  per  cent,  of  the  whole  transverse  area  of  the  screw. 
At  a  higher  velocity  than  sixty  revolutions  the  grain  was  simply 
carried  round,  and  not  propelled  forwards  at  all.  With  a  screw, 
afterwards  tried,  of  12  inches  diameter  and  12  inches  pitch,  driven 
at  seventy  revolutions  per  minute — the  most  effective  speed — 34  tons 
of  grain  per  hour  were  discharged,  and  the  power  required  to  drive 
the  screw  was  0'i25  horse-power  per  foot  run,  or  37  per  cent,  less 
than  in  the  case  of  the  previous  screw  for  the  same  delivery  of 
grain.  The  sectional  area  of  the  grain  in  motion  was  72  per  cent, 
of  the  whole  area  of  the  screw.     The  saving  in  power  in  this  case 


332  MODERN    STEAM   PRACTICE, 

was  owing  to  a  better  construction  of  parts,  as  well  as  the  quick 
pitch.  The  effect  upon  the  grain  itself  was  very  marked :  with  the 
first  screw  it  was  propelled  without  any  appreciable  agitation,  but 
with  the  quick -pitched  screw  it  was  rubbed  and  polished,  and 
thereby  improved  in  marketable  value. 

In  order  to  overcome  the  objections  experienced  with  this  screw, 
and  to  improve  still  further  if  possible  the  conditioning  of  the  grain, 
trials  were  made  with  screws  contained  in  revolving  casings.  A 
preliminary  experiment  was  made  with  a  6-inch  screw,  6  feet  long, 
with  2  inches  pitch  and  a  depth  of  blade  of  2^  inches;  a  portion  of 
the  casing  was  perforated  so  as  to  act  as  a  screen,  which  it  did 
effectually.  A  second  trial  was  then  made  with  a  30-inch  screw, 
calculated  upon  the  result  of  the  preliminary  screw  to  discharge  at 
the  rate  of  50  tons  per  hour.  The  length  of  this  screw  was  18  feet, 
and  its  pitch  12  inches,  or  fths  of  the  diameter.  The  body  of  the 
screw  was  properly  balanced,  and  revolved  upon  finely  adjusted 
rollers,  carried  in  cast-iron  frames.  A  third  experiment  was  made 
with  a  screw  12  inches  in  diameter  and  12  inches  pitch,  only  with 
the  view  of  ascertaining  the  effect  of  the  quicker  pitch.  The  results 
of  these  trials  were  as  follows : — 

The  6-incli  Screw  discharged  per  minute,  at  60  revolutions,  0*47  cubic  foot  of  wheat 
Do.  do.  80         ,,  060  ,, 

Do.  do.  100         ,,  050  ,, 

Do.  do.  140         „  o'oo  (no  delivery^. 

Showing  that,  as  the  grain  in  this  class  of  screw  is  propelled  for- 
wards by  gravity,  centrifugal  force  comes  into  action  at  high  speeds, 
and  stops  the  discharge.  With  the  30-inch  screw  a  speed  of  thirty- 
six  revolutions  per  minute  was  found  to  be  the  most  effective.  At 
this  speed  the  grain  was  carried  up  on  the  rising  side  of  the  screw 
about  5  inches  above  the  centre  of  the  casing,  and  the  discharge 
was  63^  cubic  feet,  or  about  80  tons  of  wheat  per  hour,  which  was 
a  much  higher  duty  than  had  been  calculated  upon.  The  power 
required  was  0*40  horse-power  per  foot  run ;  and  the  sectional  area 
of  the  body  of  grain  was  $6  per  cent,  of  the  whole  area  of  the 
casing.  The  12-inch  screw,  driven  at  the  same  speed  of  thirty-six 
revolutions  per  minute,  gave  10  tons  of  wheat  per  hour,  with  a 
sectional  area  of  only  17  per  cent.  The  pitch  of  fths  of  the 
diameter  proved  the  most  effective  of  those  tried.  The  use  of  these 
screws  with  revolving  casings  was  highly  advantageous  to  the  grain, 
which  became  well  rubbed  and  polished  j  and  they  also  obviated 


STATIONARY   ENGINES.  ^^^ 

the  principal  objection  experienced  with  the  screws  in  fixed  casing, 
which  harboured  dirt  and  caused  the  grain  to  be  injured  by  the 
action  of  the  screw  blades  revolving  within  it.  The  great  power 
necessary  to  drive  the  screw  with  revolving  casing  was  found,  how- 
ever, an  insuperable  objection  to  its  adoption  upon  a  large  scale. 

The  long  distances  over  which  grain  had  to  be  conveyed  hori- 
zontally in  the  warehouses,  amounting  collectively  to  7000  feet,  or 
about  I  ^  mile,  and  the  power  required  for  conveying  it  even  with 
the  best  form  of  screw,  rendered  it  expedient  to  seek  some  other 
mode  of  transport  requiring  less  power ;  and  recourse  was  therefore 
had  to  endless  travelling  bands.  After  a  few  preliminary  trials 
with  small  canvas  bands,  experiments  were  made  with  a  flat  band 
12  inches  broad,  constructed  of  canvas  and  India  rubber.  In  work- 
ing out  this  arrangement  the  first  point  to  ascertain  was  the  highest 
speed  that  could  safely  be  used  with  different  kinds  of  grain.  A 
speed  of  8  feet  per  minute  was  found  to  be  the  maximum  for  oats 
and  other  light  grain ;  and  at  this  speed  even  bran  and  flour  can 
be  conveyed  without  any  portion  being  blown  off  by  the  resistance 
of  the  air  in  the  passage  of  the  band.  A  speed  of  about  9  feet  per 
second  can  be  reached  with  heavy  clean  grain,  and  a  still  higher 
speed  with  peas ;  chaff  is  blown  off  at  a  speed  of  about  9  feet  per 
second.  The  quantity  of  grain  discharged  by  the  1 2-inch  band, 
travelling  at  a  speed  of  8  feet  per  second,  was  about  35  tons  per 
hour.  Further  trials  were  then  made  with  a  band  18  inches  broad, 
formed  of  two  plies  of  stout  canvas,  covered  with  vulcanized  india 
rubber ;  and  this  pattern  was  subsequently  adopted  for  permanent 
use.  The  band  was  made  continuous,  extending  over  a  distance 
of  37  feet,  and  was  supported  on  plain  cylindrical  carrying  rollers, 
fixed  at  intervals  of  6  feet  apart.  The  rollers  were  made  of  wood, 
with  wrought-iron  spindles  revolving  in  bearings  of  white  metal, 
and  lubricated  with  hard  grease.  The  band  was  driven  by  shaft- 
ing, and  provided  with  a  self-tightening  apparatus  similar  in  con- 
struction to  that  finally  adopted  in  the  warehouses,  consisting  of  a 
heavy  tightening  pulley  suspended  upon  the  band,  and  sliding 
vertically  between  guides.  The  maximum  quantity  of  heavy  grain 
conveyed  by  an  18-inch  band  is  at  the  rate  of  about  70  tons  per 
hour,  and  the  power  required  to  drive  the  band  when  working  at 
this  rate  is  equal  to  about  0-014  horse-power  (^Vth)  per  foot  run. 
The  grain  has  no  tendency  to  fall  off  the  band,  and  indeed  it  is 
surprising  to  see  separate  grains  at  the  edge  of  the  band  remain 


334 


MODERN   STEAM   PRACTICE. 


Steadily  in  position  whilst  passing  over  the  carrying  rollers  at  the 
highest  rate  of  speed.  Comparing  the  amount  of  power  required 
to  convey  a  stream  of  grain  at  the  rate  of  50  tons  per  hour  through 
a  distance  of  100  feet,  by  means  of  the  common  screw  in  stationary 
casing,  the  tubular  screw  with  revolving  casing,  and  the  travelling 
band  18  inches  wide,  the  following  are  the  results: — 

With  the  common  screw iS'SS  horse-power. 

,,         tubular  screw 25'00  ,, 

,,  18-inch  travelling  band I'02  ,, 

This  shows  the  great  superiority  of  the  band  over  the  screws  in 
economy  of  power. 

For  the  purpose  of  passing  the  grain  off  at  any  point  on  either 
side  of  the  main  travelling  bands,  several  contrivances  with  air- 
blast  and  brushes  driven  from  the  band  itself  were  tried,  but  with 
indifferent  success ;  both  methods  were  objectionable  on  account  of 
raising  dust,  and  the  friction  of  the  brushes  proved  injurious  to  the 
band  in  course  of  time.  The  idea  then  occurred  of  diverting  the 
stream  of  grain  by  means  of  an  upward  deflection  of  the  carrying 
band,  which  would  throw  it  clear  from  the  band  into  the  air  for  a 
short  distance,  and  in  falling  it  would  be  caught  and  led  off  by  a 
spout  to  either  side  as  required.  This  plan  proved  successful,  and 
has  been  extensively  adopted  in  connection  with  the  use  of  the 
endless  travelling  bands  for  carrying  grain.  The  throwing-off 
apparatus  is  shown  in  Fig.  212.  It  consists  of  a  couple  of  wrought- 
iron  rollers  B  B,  centred  in  gun-metal  bearings  in  a  rocking  frame  C, 
which  is  hung  in  a  movable  carriage  D  running  upon  the  timbers  E 
of  the  wooden  framing  that  supports  the  travelling  band  1 1.  The 
carriage  is  moved  to  any  position  along  the  length  of  the  band 
where  the  grain  is  required  to  be  discharged,  and  is  then  secured 
by  the  wedges  F  F  and  the  clamping  screw  G.  The  rocking  frame  C 
is  rotated  in  either  direction  by  means  of  the  screw  and  worm 
wheel  H,  so  as  to  bring  the  pair  of  rollers  B  B  into  action  at  the 
proper  position  for  throwing  the  grain  off  in  the  direction  in  which 
the  band  I  is  running;  and  the  rollers  are  turned  back  into  the 
horizontal  position  so  as  to  be  clear  of  the  band  when  the  carriage  D 
is  required  to  be  moved  to  another  position.  A  curved  spout  K  is 
attached  to  the  carriage  D  for  catching  the  stream  of  grain  in  its 
fall,  and  leading  it  off  on  either  side  of  the  band  I.  No  difficulty 
is  experienced  in  keeping  the  grain  on  the  band ;  but  it  is  found 
necessary  to  let  it  fall  upon  the  band  from  a  feeding  hopper  through 


STATIONARY   ENGINES. 


335 


a  spout  rather  less  than  half  its  breadth,  and  set  at  an  iaclination 


of  423^°,  so  as  to  gwQ  the  falling  grain  a  horizontal  velocity  nearly 
equal  to  that  of  the  band.     The  fine  dust  and  grit  thrown  off  with 


33^ 


MODERN   STEAM   PRACTICE. 


the  grain  at  this  and  other  parts  of  the  machinery  require  it  to  be 


STATIONARY   ENGINES.  337 

protected  from  injury  at  such  places.  As  the  flow  of  various  kinds 
and  conditions  of  grain  through  the  spout  from  the  hopper  varies 
considerably,  it  is  found  desirable  to  place  a  pair  of  oblique  side 
rollers  at  the  point  where  the  grain  falls  upon  the  band,  in  order  to 
give  it  a  slightly  hollow  form,  and  so  prevent  the  grain  from 
spreading.  In  passing  heavy  quantities  of  grain  along  the  bands 
to  great  distances  it  has  also  been  found  expedient  to  apply  at 
intervals  pairs  of  these  oblique  side  rollers,  which  are  carried  on 
movable  frames  that  can  be  set  at  any  required  spot 

The  cross  bands  J  J  (Fig.  213),  for  conveying  the  current  of  grain 
in  a  direction  at  right  angles  to  the  main  bands,  are  driven  from  the 
lower  or  return  half  of  the  main  band,  which  is  passed  half  round 
a  driving  roller  R,  at  each  of  the  cross  bands;  and  the  motion  is 
communicated  from  this  roller  to  the  cross  bands  through  a  pair  of 
mitre  wheels  S,  having  a  clutch  T  for  throwing  the  driving  shaft  in 
and  out  of  gear.  The  cross  bands  or  other  machinery,  such  as  the 
centrifugal  distributing  fan,  can  also  be  driven  by  depressing  the 
return  half  of  the  main  band  by  a  roller  carried  in  a  rocking  frame 
so  as  to  bring  the  band  well  into  contact  with  a  fixed  roller  situated 
underneath,  which  can  then  communicate  the  required  motion  for 
any  purpose;  and  this  simple  mode  of  taking  off  power  from  the 
main  bands  has  proved  of  service  in  many  ways. 

A  revolving  fan  for  spreading  the  grain  over  the  floors  of  the 

warehouses,  and  for  ventilating  it  and  improving  its  condition,  has 

been  used  with  success.     This  fan  is  carried  upon  an  upright  shaft, 

driven    from   the    main  band    by  the    same   arrangement  as   that 

described  for  driving  the  cross  bands.     As  the  band  is  required  to 

travel  in  opposite  directions,  the  fan  is  made  with  straight  radial 

vanes,  to  allow  of  its  revolving  in  either  direction.     The  grain  is  led 

by  a  spout  on  to  the  top  of  the  fan,  and  to  avoid  the  separation  of 

heavy  and  light  particles  in  the  mass,  and  to  spread  it  as  evenly 

over  the  floor  as  possible,  the  body  of  the  fan  has  a  conical  form, 

the  alternate  blades  being  made  of  a  different  length  and  shape,  as 

shown  in  the  enlarged  view.  Fig.  214.     A  hinged  tongue  is  placed 

in  the  end  of  the  delivery  spout  above  the  fan,  and  the  discharge  of 

the  grain  can  be  directed  to  any  particular  spot  by  turning  this 

tongue  round  in  the  required  position.     The  fan  is  placed  9^^  feet 

above  the  floor,  and  at  its  usual  speed  of  250  revolutions  per  minute 

it  deposits  the  grain  in  a  circle  of  45  feet  diameter. 

Five  hydraulic  cranes  for  discharging  cargo  are  fixed  in  towers 

22 


338 


MODERN    STEAM   PRACTICE. 


specially  constructed  in  the  warehouses,  as  shown  in  Fig.  2 1 5.  These 
cranes  are  fitted  for  raising  grain  in  tubs  containing  2 1  cwts.  each, 
at  a  rate  of  50  tons  per  hour  under  the  most  favourable  conditions; 

and  they  are  also  employed  for 
landing  sacks,  casks,  and  other 
merchandise  on  to  the  quay,  or 
to  any  of  the  warehouse  floors. 
The  lifting  chain  has  an  extreme 
range  of  130  feet,  and  the  jib  an 
extreme  projection  of  24  feet  be- 
yond the  quay;  a  traversing  mo- 
tion of  7^  feet  is  given  to  the 
foot  of  the  jib,  but  this  is  only 
required  for  the  largest  class  of 
vessels.  The  motions  are  all  ef- 
fected by  hydraulic  power,  under 
the  control  of  one  man  stationed 
on  a  platform  in  the  tower.  The 
grain  is  filled  into  tubs  in  the 
hold  of  the  vessel,  and  to  find  the 
best  form  for  these  tubs  has  been 
matter  of  some  difficulty.  The 
first  form  used  was  the  ordinary 
tipping  tub,  which  has  by  long 
experience  been  found  to  answer 
best  for  the  discharge  of  coal, 
salt,  gravel,  &c.  The  next  form  tried  required  no  tipping,  but  was 
fitted  with  a  cone  to  deliver  the  grain  through  the  bottom.  The 
form  that  proved  on  the  whole  most  satisfactory  also  requires  no 
tipping,  and  is  fitted  with  a  butterfly  valve  in  the  bottom ;  when  the 
tub  is  in  position  for  emptying  into  the  upper  receiving  hopper  P, 
this  valve  is  opened  by  a  lever  from  the  platform  on  which  the 
man  is  stationed  to  work  the  crane.  The  time  required  by  this  tub 
for  emptying  itself  depends  on  the  kind  and  quality  of  the  grain 
which  it  contains:  with  wheat  in  good  and  dry  condition  it  is  five 
seconds,  with  barley  seven  seconds,  and  with  Indian  corn  from 
nine  to  ten  seconds. 

The  hopper  P  (Fig.  216),  into  which  the  grain  lifted  by  the  crane  to 
the  top  of  the  warehouse  is  dropped  from  the  tub,  holds  about  8  tons, 
and  froni  this  hopper  the  grain  is  diverted  into  two  streams,  and 


Fig.  214. — Distributing  Fan. 


STATIONARY   ENGINES. 


339 


N,  Distributing  fan.     o.  Crane. 

p.  Upper  receiving  hopper. 

Q,  Band.     R,  Receiving  hopper. 

s.  Weighing  hopper. 

T  T,  Distributing  hoppers. 

U  u,  Spouts.     V,  Arched  subway. 

W,  Elevator,     x,  Filling  hopper. 


Fig,  21$. — Transverse  Section  of  Warehouse,  showmg  Hoisting  Gear,  &c. 


340 


MODERN   STEAM   PRACTICE. 


allowed  to  flow  through  the  spouts  fitted  with  regulators  on  to  two 
1 8-inch  inclined  bands  Q,  driven  by  one  hydraulic  engine.     One  of 


these  bands  would  be  sufficient  to  carry  the  grain  delivered  by  the 
crane,  but  two  are  employed  to  spread  it  out  more,  and  to  separate 


STATIONARY   ENGINES.  34! 

the  dust  from  it  when  required.  This  separation  is  effected  by  an 
inclined  flap  fixed  in  the  inner  receiving  hopper  R,  into  which  the 
two  bands  Q  convey  the  grain  from  the  outer  hopper  P.  From  the 
hopper  R  the  grain  is  allowed  to  drop  through  the  valve  into  the 
I -ton  weighing  hopper  S;  after  which  it  is  delivered,  by  a  simple 
arrangement  of  doors  in  the  bottom  of  the  weighing  hopper,  to 
either  side  of  the  distributing  hopper  T,  from  whence  it  passes  on 
to  one  or  other  of  the  18-inch  bands  II  which  traverse  the  entire 
length  of  the  warehouses.  The  man  stationed  at  the  weighing 
machine  S  regulates  the  flow  of  grain  from  the  several  hoppers, 
and  records  the  quantity  passed. 

Two  main  lines  of  18-inch  bands,  made  to  run  in  either  direction, 
are  necessary  for  the  convenient  working  of  these  warehouses.  A 
vessel,  for  instance,  lying  at  the  west  block  of  the  warehouses  may 
require  her  cargo  deposited  at  either  end  of  that  block,  or  at  any 
spot  in  either  of  the  other  two  blocks;  and  at  the  same  time 
another  vessel  lying  at  the  east  block  opposite  may  have  its  cargo 
housed  in  the  west  block.  Thus  it  often  happens  that  two  streams 
of  grain  are  flowing  in  opposite  directions,  and  that  one  or  both  of 
these  is  carried  right  round  the  warehouses.  The  bands  in  the 
east  and  west  blocks  are  divided  into  two  lengths,  and  the  bands 
connecting  these  two  blocks  and  passing  through  the  north  block 
are  in  one  length.  Each  band  is  fitted  with  a  separate  tightening- 
up  apparatus,  seen  in  Fig.  213  at  M;  and  is  driven  by  a  separate 
hydraulic  engine  N,  of  about  3  horse-power,  having  two  cylinders, 
and  fitted  with  reversing  and  regulating  gear,  which  can  be  con- 
trolled from  any  point  along  the  entire  length  of  the  band.  At 
each  point  where  the  flow  of  grain  has  to  be  diverted  from  a  main 
band  to  a  cross  band,  a  fixed  throwing-off  carriage  is  stationed. 
Two  movable  throwing-off  carriages  are  provided  on  each  main 
band,  for  casting  the  grain  off  the  band  into  the  wooden  descending 
spouts,  85^  inches  square,  which  convey  it  from  the  top  of  the 
warehouse  to  any  floor  in  the  building.  There  are  fifty-six  of  these 
spouts  U  U,  Fig.  215,  passing  from  the  upper  machinery  floor  down 
to  the  lower  12-inch  bands  in  the  arched  subway  V  V  below  the  quay 
level;  they  are  provided  with  sliding  doors  at  the  different  floor 
levels,  to  admit  of  the  grain  being  shovelled  into  waggons  on  the 
railway  which  traverses  the  centre  of  the  block,  or  on  to  the  lower 
12-inch  bands  for  conveying  to  the  elevators.  A  number  of  other 
shoots  at  suitable  intervals  are  built  in  the  walls  of  the  warehouses 


342  MODERN   STEAM   PRACTICE. 

fronting  the  dock  at  the  levels  of  the  several  floors,  and  each  is 
provided  at  the  first  floor  with  a  delivery  outlet,  to  which  a  movable 
spout  is  hooked  on,  for  delivering  grain  from  the  warehouse  into 
vessels.  The  arrangement  of  the  lowering  band  machinery  is  a 
counterpart  of  the  upper,  but  upon  a  smaller  scale,  and  without  the 
movable  throwing-ofif  carriages  provided  on  the  upper  bands,  which 
are  not  required  for  the  lower.  These  lower  bands  are  employed 
for  the  purpose  of  conveying  grain  from  any  of  the  descending 
spouts  to  any  of  the  five  elevators  W,  which  are  fixed  in  the  crane 
towers.  The  grain  conveyed  along  these  1 2-inch  main  bands  is 
thrown  upon  the  1 8-inch  cross  bands,  which  deliver  it  into  the 
hopper  X,  supplying  the  elevator  w;  one  1 8-inch  cross  band  will 
carry  the  full  quantity  of  grain  conveyed  by  the  two  1 2-inch  bands, 
and  the  cross  bands  are  arranged  to  receive  their  motion  from 
either  line  of  the  main  bands.  Much  of  the  grain  discharged  from 
the  vessels  in  the  dock  is  sorted  upon  the  quay,  and  is  then  thrown 
by  hand  into  the  hopper  X  of  the  elevators. 

The  elevator  for  raising  the  grain  from  the  bottom  to  the  top  of 
the  warehouses  is  shown  on  a  larger  scale  in  Fig.  217.  The  wrought- 
iron  bucket  w,  capable  of  containing  about  21  cwts.,  is  slung  from 
the  lifting  chain  by  an  arrangement  of  bars  and  levers,  and  provided 
with  guiding  rollers  running  between  the  upright  timbers,  so 
arranged  that  on  reaching  the  top  the  bucket  tips  over,  and  dis- 
charges the  grain  into  the  hopper  Y.  This  hopper  delivers  the 
grain  upon  the  same  inclined  cross  bands  Q  that  convey  it  from 
the  outer  crane  hopper  P.  The  bottom  hopper  is  made  in  two 
parts,  the  upper  of  which  X,  protected  by  a  grating,  receives  the 
bulk  of  the  grain,  while  the  lower  compartment  Z  contains  only  one 
charge  at  a  time  for  the  elevator  bucket  W,  and  is  separated  from 
the  upper  portion  by  a  sliding  valve.  The  descending  speed  of  the 
bucket  having  been  checked,  as  it  approaches  the  bottom  it  strikes 
the  arm  of  the  tappet  lever  A,  which  closes  the  valve  between  the 
two  compartments  X  and  z  of  the  hopper;  and  continuing  its 
descent  still  more  slowly,  the  bucket  strikes  another  tappet  arm  B, 
which  disengages  the  iron  flap  C  that  covers  the  front  of  the  lower 
compartment  Z;  this  flap,  falling  forwards  by  the  weight  of  the 
grain  behind  it,  shoots  the  contents  of  the  lower  hopper  z  into  the 
bucket  W.  As  soon  as  the  bucket  has  received  its  charge  the 
motion  is  reversed  for  lifting.  Beginning  to  ascend  at  a  moderate 
speed,   the  bucket   closes  the  flap  C  of  the  lower  hopper,   which 


STATIONARY   ENGINES.  343 

is   held   up    against   it,   as   shown   dotted,    by   means   of    spring 


Fig.  217. — Elevator  for  Lifting  Grain  into  Warehouse. 

A,  Tappet  lever,     b,  Tappet  arm.     c,  Flap,     d  d,  Spring  catches,     o,  Chain,     w,  Elevator. 
X,  Filling  hopper,     v.  Receiving  hopper,     z,  Filling  compartment. 

catches  DD;  and  the  bucket  then  strikes  the  tappet  lever  A  of  the 


344  MODERN   STEAM   PRACTICE. 

hopper  valve,  and  re-opens  the  communication  between  the  two 
compartments  X  and  z.  The  speed  is  then  accelerated  until  the 
bucket  arrives  near  the  receiving  hopper  Y,  when  it  is  again  retarded 
before  the  grain  is  shot  out.  The  motion  of  the  bucket  is  regulated 
by  self-acting  gear.  These  bucket  elevators  are  intended  to  raise  the 
grain  at  the  rate  of  50  tons  per  hour,  but  they  are  capable  of  being 
worked  at  a  higher  speed.  The  chain  O  of  the  crane  is  employed 
for  lifting  the  bucket  of  the  elevator;  but  it  has  been  found  expedient, 
on  account  of  the  demands  of  the  traffic,  to  make  the  elevators  also 
independent  of  the  cranes,  and  therefore  separate  hydraulic  cylinders 
with  their  adjuncts  have  been  supplied  for  working  the  former. 

Trials  have  been  made  for  lifting  grain  by  means  of  dredging 
machines,  and  it  has  been  found  that  with  a  dredger  30  feet  long 
50  per  cent,  of  the  applied  power  proved  effective.  Experiments 
have  also  been  made  for  raising  corn  by  air  pressure  or  suction^ 
and  the  results  obtained  are  sufficient  to  prove  that  this  system 
possesses  certain  advantages  over  the  plan  in  use;  but  it  is  sur- 
rounded with  difficulties  and  obstructions  which  must  be  removed 
before  it  can  be  employed  with  advantage  upon  a  large  scale. 

Casks,  bags,  and  other  merchandise  are  raised  or  lowered  either 
by  hydraulic  cradle  hoists  or  by  jiggers.  There  are  twelve  hydraulic 
hoists  of  the  ordinary  construction,  each  capable  of  lifting  a  load 
of  I  ton  to  the  uppermost  floor  of  the  warehouses.  They  are  found 
also  serviceable  in  breaking  out  the  cargoes  from  the  fore  and  aft 
hatchways  of  a  vessel  lying  with  its  centre  hatch  in  line  with  the 
crane  or  elevator.  For  this  purpose  the  lifting  chain  is  disconnected 
from  the  cradle  of  the  hoist,  and  led  through  a  snatch  block  fastened 
to  some  part  of  the  vessel.  The  twenty  single-acting  outside 
jiggers,  originally  constructed  only  for  lowering  loads  by  friction, 
have  been  supplied  with  auxiliary  hydraulic  power  for  lifting  loads 
from  6  to  7  cwts.  Twelve  double-acting  jiggers,  for  loads  up  to 
locwts.,  have  been  added  in  the  centre  of  the  warehouses,  for  lifting 
or  lowering  goods  to  railway  waggons ;  they  are  so  constructed  that 
they  can  be  used  singly  or  together,  and  for  lifting  or  lowering. 
Both  machines  may  be  alternately  lowering  goods  into  waggons 
below  from  any  of  the  floors  of  the  warehouses,  or  by  means  of  the 
water  pressure  they  may  both  be  raising  goods  from  the  waggons 
to  any  of  the  floors;  or  one  side  of  the  machine  may  be  lowering 
whilst  the  other  is  hoisting  goods  from  the  hatchways  of  vessels  to 
which  the  lifting  chain  has  been  led. 


HYDRAULIC    MACHINE    TOOLS. 


HYDRAULIC  MACHINES   FOR   RIVETTING  AND   FLANGING   PLATES,   RIVETTING   KEELS,  AND  ANCLE-IRON 


OR   BEAM   STRAIGHT 


STATIONARY   ENGINES.  345 

HYDRAULIC   MACHINE   TOOLS. 

See  Machine  Tools  and  Hammers — Appendix. 

The  application  of  hydraulic  pressure  to  sin^ie  machine  tools 
may  be  said  to  date  from  about  the  year  1847,  when  Mr.  Fox  used 
the  Bramah  press  for  the  purpose  of  forging.  Since  then  a  variety 
of  hydraulic  tools  have  been  introduced,  amongst  Avhich  may  be 
mentioned  those  for  forging  and  welding,  rivetting  boilers  and  ships' 
frames,  fixing  boiler  tubes,  for  bridge  and  girder  work,  bending 
angle  irons,  flanging  plates,  shears  for  cutting  chain  cables,  beam 
straighteners  or  benders,  &c. 

Fig.  I  in  the  Plate  shows  a  portable  rivetter,  having  the  cylinder 
A  between  the  fulcrum  B  and  the  rivetting  dies  CC. 

In  designing  portable  rivetters  for  ship  and  bridge  rivetting  some 
form  of  flexible  pipe  is  necessary,  to  convey  the  water  to  the 
working  parts;  and  copper  pipes  or  india-rubber  hose  are  used  for 
this  purpose.  The  cranes  carrying  the  rivetters  are  either  attached 
to  fixed  posts,  or,  as  shown  by  fig.  2,  the  posts  are  movable  on  a 
trolly,  and  by  means  of  the  walking  pipes  B  B,  connected  to  the  stop 
valve  A  and  a  swivel  joint  C,  the  whole  apparatus  may  be  moved  at 
pleasure.  By  means  of  connections  at  D  and  E  at  the  foot  of  the 
crane  post,  the  pressure  is  conveyed  by  the  pipe  1 1  to  swivel  Q, 
where  the  walking  pipes  I'l'  convey  the  water  to  the  hydraulic  lift 
G  on  the  carriage  F,  and  a  copper  pipe  H  conveys  the  pressure  to 
the  rivetter.     Such  a  machine  will  put  in  over  2000  rivets  per  day. 

Fig.  4  shows  an  arrangement  designed  for  the  rivetting  of  ships' 
keels,  where  the  small  depth  of  the  rivet  heads  and  their  great  size 
requires  special  arrangement.  A  post  BB  carrying  a  turntable  revolves 
on  the  trolly  A,  a  pair  of  levers  G,  attached  to  a  carriage  D,  carry  the 
rivetter  E,  which  can  be  raised  at  pleasure  to  suit  the  work,  and  is 
kept  vertical  by  means  of  a  parallel  motion  F;  the  whole  is  counter- 
balanced by  the  weight  N.  The  keels  of  the  City  cf  Rome  and 
Servia  were  rivetted  by  such  a  machine,  and  the  advantage  of  so 
powerful  a  method  of  closing  up  the  rivets  is  evident  when  it  is 
considered  that  the  keels  of  such  large  vessels  are  made  up  of  a 
number  of  plates  and  bars  of  great  thickness.  As  a  matter  of 
experiment,  as  many  as  24  plates,  each  }^  inch  thick,  have  been 
closed  up  or  rivetted  apparently  into  a  solid  piece,  showing  what 


346  MODERN   STEAM   PRACTICE. 

work  can  be  done  by  a  suitable  combination  of  pressure  and  per- 
cussive action. 

Fig.  3  shows  a  machine  for  flanging  plates.  On  the  bottom 
casting  B  a  matrix  D  is  fitted,  upon  which  the  plate  to  be  flanged  is 
placed,  and  by  means  of  the  block  E  descending  the  plate  is  turned 
over  upon  its  edges;  to  prevent  buckling  a  cylinder  F  is  fitted  with 
a  plunger  H  carrying  a  table  G  on  its  ram,  by  means  of  which  the 
plates  can  be  gripped  between  the  table  G  and  the  block  E. 

Fig.  5  shows  a  machine  for  bending  or  straightening  angle  irons 
and  beams.  The  piece  to  be  bent  rests  upon  the  abutting  blocks 
B  B,  which  are  adjustable  by  right-  and  left-handed  screws  AA,  and  by 
means  of  a  tappet  gear  the  supply  of  water  and  also  the  travel  are 
regulated  according  to  the  work  required,  thus  insuring  exact  repe- 
tition and  accuracy  in  work. 

A  very  extensive  adoption  of  hydraulic  power  to  machine  work 
has  been  made  at  the  French  arsenal  at  Toulon,  where  amongst 
others  two  punching  and  shearing  machines,  and  also  angle-iron 
benders  similar  to  fig.  5  are  used,  capable  of  exerting  lOO  tons  of 
pressure.  There  is  also  a  stationary  rivetting  machine  exerting 
40  tons  pressure,  and  a  number  of  portable  rivetting  machines  for 
rivetting  the  cellular  bottoms  and  decks  of  ships,  at  a  distance 
of  1300  feet  from  the  accumulator.  The  pressure  used  is  1500  lbs. 
per  square  inch.  It  appears  that  less  steam  power  is  required  by 
this  hydraulic  arrangement  than  would  otherwise  be  the  case,  and 
the  author  of  the  paper  to  which  we  are  at  present  indebted  says,  "A 
moment's  consideration  will  show  that  when  gearing  is  used  the 
prime  mover  must  be  equal  to  the  maximum  demand  which  can 
be  made  on  it  at  any  moment.  The  accumulator,  however,  affords 
a  smaller  engine  the  opportunity,  when  not  otherwise  fully  engaged, 
of  storing  up  by  easy  stages  an  amount  of  power  equal  to  the  greatest 
instantaneous  demand  likely  to  be  made,  and  as  long  as  the  work 
required  is  not  equal  to  the  power  of  the  pumps,  this  process  of 
putting  by  power,  as  it  were,  is  going  on,  consequently  a  much 
smaller  prime  mover  will  suffice,  which  means  less  boiler  power  and 
a  more  economic  use  of  steam."  ^ 

^  See  a  valuable  paper  and  drawings  in  Trans.  Inst.  Engineers  and  Shipbuilders  in  ScoU 
land,  vol.  xxiv.,  by  Mr.  R.  H.  Tweddell  of  London,  who  has  been  of  late  years  highly 
successful  in  applying  hydraulic  pressure  to  tools  on  a  complete  scale. 


MARINE    ENGINES. 


THE    OSCILLATING   ENGINE. 

The  vibrating  or  oscillatmg  etigine  mirodviCQd  by  Maudslay  in  1827, 
with  its  varied  modern  improvements,  is  very  suitable  for  paddle- 
wheel  steamers,  the  comparatively  small  space  it  requires  fitting  it 
admirably  for  this  class  of  vessel.  It  is  the  most  direct-acting  kind 
of  engine  which  we  have;  the  piston  rod  is  connected  to  the  crank 
pin  directly,  thus  saving  height  in  the  engines  where  that  is  a 
desideratum,  and  the  weight  is  most  satisfactorily  placed,  being 
neither  too  high  nor  too  low  in  the  ship.  The  many  examples — 
from  the  small  river  boats  on  the  Thames  of  30  horse-power  collec- 
tively, to  large  ocean  steam  ships  such  as  the  Great  Eastern,  the 
largest  ship  as  yet  constructed,  with  oscillating  engines  for  the 
paddle  wheels  of  1000  nominal  horse-power  collectively — all  bear 
testimony  to  the  success  of  the  oscillating  type  of  engine.  It  may 
be  regarded  as  the  only  example  left  of  the  many  classes  of  engines 
that  have  been  successfully  applied  to  paddle-wheel  ships;  and 
from  our  being  able  to  couple  the  crosshead  of  the  piston  rod 
directly  on  the  crank  pin,  and  keep  the  weight  of  the  machinery 
below  the  deck,  the  oscillating  engine  is  likely  to  remain  long  in  use 
for  shallow  river  boats  propelled  by  paddle  wheels,  for  undoubtedly 
this  method  of  propulsion  possesses  many  advantages  over  the 
screw  propeller  for  vessels  of  light  draught,  especially  when  they 
are  built  to  attain  great  speed. 

The  peculiar  motion  of  these  engines — the  cylinders  vibrating  on 
central  hollow  trunnions — requires  the  parts  to  be  nicely  balanced ; 
and  as  the  piston  rod  takes  the  side  strain  and  the  strains  imparted 
by  the  action  of  the  steam  on  the  piston,  it  requires  to  be  made  of 
greater  diameter  than  for  ordinary  engines,  where  it  is  only  sub- 
jected to  tension  and  compressive  stress. 

The  tnmnions  should  be  so  placed  that  the  preponderance  of  the 
weight  of  the  cylinder  is  towards  the  bottom,  by  which  means  the 


348 


MODERN    STEAM    PRACTICE. 


strain  on  the  piston  rod  is  not  so  much  felt,  and  when  the  crossheads 
are  uncoupled  from  the  crank  pins  the  cylinders  are  not  so  liable 
to  tilt.  This  will  be  found  a  great  convenience  when  undergoing 
repairs  at  sea.  The  larboard  and  starboard  trunnions  are  for  the 
steam,  which  passes  through  a  belt  cast  along  with  the  cylinder 
into  the  valve  casing.  The  faces  for  the  valves  are  generally  of  the 
three-ported  type,  two  ports  are  for  the  steam  and  a  central  one  for 
the  exhaust.  The  two  central  trunnions  are  for  the  exhaust  steam, 
which  passes  into  the  belt  around  the  cylinder,  and  then  into  the 


Fig.  220. — Cylinder. 

A,  Cylinder.  B  B,  Trunnions.  c,  Cylinder  cover. 
D,  Bottom  cover.  E  E,  Valve  faces.  F  F,  Steam 
passages.     G,  Exhaust  passage. 


Fig.  221. — Trunnion  Pipe  and  Stuffing  Box. 

A,  Trunnion  pipe.  B,  Gland  for  stuffing  box.  c,  Cy- 
linder. D,  Throttle-valve  pipe.  E,  Bracket  for 
supporting  do.     F,  Pillow  block.     G,  Frame. 


condenser  through  the  hollow  trunnions;  thus  one  half  of  the  belt 
allows  the  steam  from  the  boiler  to  pass  into  the  valve  casing,  and 
the  other  half  acts  as  a  passage  to  the  condenser,  the  division  being 
formed  by  feathers  or  bars  cast  in  the  cylinder. 

The  tntnnion  pipes  for  the  steam  and  exhaust  are  fitted  with  glands 
and  packing  spaces  formed  in  each  trunnion ;  the  former  are  bolted 
to  the  branch  pipes,  which  are  supported  by  brackets  bolted  to  the 
bottom  frames,  and  the  latter  are  bolted  to  the  condenser  casting, 


MARINE   ENGINES. 


349 


and  packed  with  hemp  or  other  packing,  similar  to  the  piston-rod 
packing.  The  branch  pipes  are  bent, upwards,  and  on  the  top  flanges 
are  placed  the  throttle  and  expansion  valves;  thus  an  immovable 
pipe,  in  communication  with  the  valve  casing  which  vibrates  along 
with  the  cylinder,,  is  made  perfectly  steam-tight. 

The  steam  valves  are  generally  formed  in  duplicate,  one  being 
placed  on  each  side  of  the  cylinder;  while,  for  long-stroked  engines 
of  this  class,  four  valves  have  been  introduced.  In  the  former  case 
the  horizontal  line  of  location,  or  centre  line  of  the  exhaust  port,  is 
on  the  centre  line  of  the  trunnions;  in  the  latter,  the  valves  are 
placed  above  and  below  the  trunnion  centre  line,  with  the  object 
of  reducing  the  length  of  the  steam  ports,  and  thereby  saving  steam 
at  each  stroke  of  the  engine,  and  consequently  fuel.  The  object  of 
placing  the  valves  on  each  side  of  the  cylinder  is  to  balance  it, 
each  valve  is  also  greatly  reduced  in  size;  but  notwithstanding  that 
the  valve  gearing  is  more  complicated,  double  valves  are  generally 
adopted,  as  they  secure  a  neater  and  more  equally  balanced  cylin- 
der. One  valve  may  be  used  for  very  small  power,  and  a  weighted 
lever  placed   on  the  opposite   side   of  the  cylinder  to  balance  it. 

The  stuffing  box  and  gland  for  the  piston 
rod  of  the  oscillating  engine  is  made  very 
deep,  giving  a  large  bearing  surface  to  take 
the  side  strain  caused  by  the  vibration  of  the 
cylinder;  and  in  cases  where  the  proportions 
allow  of  great  space  between  the  end  of  the 
crosshead  and  the  top  of  the  gland  bolts, 
the  part  cast  along  with  the  cylinder  cover 
can  be  made  of  any  convenient  length,  with 
a  brass  bush  inserted  at  the  bottom,  and  the 
necessary  bushes  and  glands  at  the  top  of 
the  long  neck  piece,  as  in  ordinary  arrange- 
ments. Care  must  be  taken  to  have  a 
small  amount  of  clearance  all  round  the 
piston  rod  below  the  stuffing  box,  or  to  insert  a  very  deep  bush. 

The  condenser  in  the  ordinary  injection  system  is  placed  between 
the  cylinders,  and  in  the  surface  system  it  is  placed  on  the  centre 
line  of  the  ship,  behind  or  before  the  cylinders  as  the  case  may  be. 
The  latter  is  not  so  compact  an  arrangement  as  the  former,  but  it 
is  necessary,  as  the  space  taken  up  by  the  surface  system  will  not 
allow  the  condenser  to  be  placed  as  with  plain  injection. 


Fi 


222.  —  Cylinder-  cover 
Stuffing  Box. 
A,  Stuffing  box.     B,  Gland. 
c,  Bottom  bush. 


350 


MODERN   STEAM   PRACTICE. 


The  air  pumps  for  the  injection  system  are  either  single  or  in 
duphcate,    lying   at   an    angle;    when    one    pump    is    used    it    is 


Fig.  223. — single  Air  Pump  and  Condenser. 
A,  Condenser,     b,  Air  pump,     c,  Air-pump  cover.     D,  Exhaust  passage.     E,  Hole  for  injection  valves. 

generally  placed  forward  in  connection  with  the  cylinders ;  when 
two  are  adopted,  one  is  forward  and  the  other  aft  of  the  centre  line 
of  the  engine.     They  are  worked  directly  from  the  intermediate 


Fig.  224. — Double  Air  Pump    and  Condenser. 
A,  Condenser,     b  b.  Air  pumps,     c  c.  Air-pump  covers.     D,  Exhaust  passage.     E  E,  Hot  wells. 

crank  shaft,  with  one  rod  for  the  single  pump  and  two  rods  on  the 
same  crank  for  the  double  arrangement.  The  rods  have  suitable 
crossheads  for  taking  the  crank  pin,  and  their  bottom  ends  are 
fitted  with  pins  and  joints,  secured  with  large  brass  nuts  through 
the  air-pump  buckets,  with  trunks  fitted  to  them,  which  serve  as 
guides,  instead  of  crossheads  and  guide  bars.     The  bottom  part  of 


MARINE   ENGINES. 


351 


Fig.  22s. — Double  Air  Pump  and  Condenser,  arranged 

vertically. 

A,  Condenser.     B  B,  Air  pumps,     c  c,  Covers  for  do. 

3   Exhaust  passage.     E  E,  Hot  wells.     F,  Rocking  beam. 


the  connecting  rod  has  a  hole  bored  up  through  it,  and  is  fitted 
with  an  internal  steel  rod  which  can  adjust  the  bottom  brasses  with 
a  screwed  key  and  jib. 

In  some  examples  the  air  | 

pumps  have    been   placed  (p 

vertically,  one  on  each  side  \    ....••■'"''"■■-- '""""--'.    j' 

of  the  centre  line  of  the 
engines,  having  a  single 
connecting  rod  from  the 
crank  pin,  taking  a  vibrat- 
ing beam  placed  above  the 
pumps,  to  which  the  buck- 
ets are  connected  at  the 
ends  by  rods  and  guiding 
trunks,  the  point  of  con- 
nection for  the  main  rod 
being  placed  within  the 
centre  line  of  the  forward 
pump,  whereby  less  throw  is  required  for  the  crank  on  the  inter- 
mediate shaft.  This  plan,  however,  is  not  so  good  as  working  the 
pump  directly  from  the  shaft,  the 
connecting  rod  taking  a  crosshead 
on  the  air-pump  rod,  and  which  is 
guided  with  cast-iron  guide  frames 
bolted  to  the  top  of  the  air-pump 
cover. 

The  air-pump  bucket  head  and  foo^  | 
'valves{Fig.  227)  are  fitted  with  round 
discs  of  India  rubber,  working  on 
suitable  gratings  cast  on  the  bucket 
and  valve  seats,  with  the  necessary 
guards  to  prevent  or  limit  the  lift  of 
the  discs.  These  valves  are  intro- 
duced to  obviate  the  disagreeable 
knocking  action  felt  in  all  pumps  with  metallic  valves  when  working 
at  great  speed.  Instead  of  one  large  disc  of  India  rubber,  several 
smaller  ones  have  been  fitted  to  the  air-pump  bucket  head  and  foot 
valve,  but  for  slow-speed  engines  one  disc  is  quite  sufficient.  In  all 
pump  arrangements  doors  should  be  provided  to  inspect  the  valves, 
without  requiring  to  draw  the  air-pump  bucket ;  in  this  respect  it  is 


Fig.  226. — Single  Air  Pump  and  Condenser, 

arranged  vertically. 

A,  Condenser.     B,  Air  pump,    c,  Air-pump  cover. 

D  D,  Exhaust  passages.     E,  Discharge  passage. 

F  F,  Pillow  blocks. 


352 


MODERN   STEAM   PRACTICE. 


more  convenient  to  use  smaller  discs  for  the  foot  and  head  valves, 
the  latter  being  placed  above  the  bucket,  at  the  bottom  of  the  hot 
well,  which  is  also  fitted  with  a  door  to  admit  of  occasional  inspection. 


1 -w —  ■■     vZH 

- 

r,— — — r:^^ 

£m 

A 

pT ^ -X 

\ 

i               \ 

Fig.  227. — Bucket  and  Head  Valve. 

A,  Head-valve  seat,     b,  DisC' of  India  rubber,     c,  Guard.     D,  Bucket,     e,  Disc  of  india  rubbet 
F,  Guard.     G,  Joint  and  pin  for  rod. 

Cranked  shaft. — As  the  intermediate  cranked  shaft  in  some  engines, 
more  especially  those  of  large  power,  has  caused  great  trouble,  plain 
shafts  have  been  substituted,  and  the  air  pumps  worked  by  means  of 
eccentrics.  A  single  eccentric  may  be  adopted  for  a  small  diameter 
of  pump;  but  when  the  pump  is  large  it  is  preferable  to  have  two, 
with  rods  connected  to  a  crosshead,  with  a  single  central  rod  for 


MARINE   ENGINES. 


353 


taking  the  joint  at  the  bottom  of  the  trunk.  In  this  way  ample 
bearing  surface  is  obtained,  and  the  shaft  is  not  so  Hable  to  be 
fractured  as  when  the  strain  is  re- 
ceived on  the  middle.  The  eccen- 
trics should  also  be  placed  as  near 
the  main  bearings  in  the  head- 
stock  or  top  frame  for  taking  the 
shafting  as  can  be  conveniently 
done,  as  the  strain  on  the  inter- 
mediate   shaft    is    thereby    better       Fig.  228.- Cranked  shaft  for  Air  Pump. 

,.         .,  1  A,  Cranked  shaft.     B,  Main  bearing,     c,  Bearing 

QlSiriDUtea.  for  eccentric,     d.  Crank  pin  for  air-pump  rod. 

The   feed  and  bilge  pumps   are  e.  Part  for  the  piston-rod  crank. 

sometimes    worked    off    a    double 

lever  arm,  fitted  to  the  end  of  the  trunnions ;  this  plan  necessitates 
a  large  diameter  of  pump,  having  a  very  short  stroke,  owing  to  the 
length  of  the  vibrating  arm.     This  arrangement  does  not  make  so 


1) 

V 
A 

C 

B 

E 

Fig.  229. — Feed  and  Bilge  Pumps. 

A,  Feed  pump,     b.  Bilge  pump,     c,  Rocking  arm  and  rods.     D,  Plunger  and  stuffing  bo-i. 

E,  Suction  valve.     F,  Discharge  valve.     G,  Relief  valve  and  spring. 

effective  a  pump  as  when  the  stroke  is  increased,  giving  less  dia- 
meter of  plunger,  which  can  be  readily  attained  by  placing  the 
pumps  on  each  side  of  the  air  pump,  and  connecting  them  to  the 
crosshead  fitted  to  the  top  of  the  trunk,  when  they  have  the  same 

23 


354 


MODERN   STEAM   PRACTICE. 


length  of  stroke  as  the  air  pump.     In  this  case  the  one  acts  as  the 
feed  pump,  and  the  other,  technically  termed  the  "bilge  pump," 
pumps  out  the  water  that  accumu- 
lates in  the  hold  of  the  ship.     The 
feed-pump  valves  are  formed  either  C 

of  metal  or  discs  of  india  rubber; 
but  as  the  bilge  pump  takes  in  many- 
foreign  substances,  metallic  valves  of 
the  flap  type  are  preferable  for  it. 
Such  valves  answer  very  well  for 
moderate  speed,  but  should  never  be 


Fig.  230. — Feed  Pump. 
A,  Feed  pump.     B,  Ram  for  do.     c,  Pin  for  taking  the  air-pump  crosshead  at  one  end,  and  bilge  pump 
at  the  other  end.    d.  Suction  valve.    E,  Discharge  valve.    F,  Relief  valve  and  spring.     G,  Air  vessel. 

adopted  for  quick-going  engines,  as  they  would  soon  be  knocked 
to  pieces,  and  the  noise  they  make  at  each  stroke  is  far  from 
agreeable. 

The  bottom  bed  plate  for  taking  the  trunnion  blocks  is  a  light 
casting  of  a  T  section ;  the  pillow  blocks  for  the  larboard  and  star- 
board trunnions  are  sometimes  cast  on,  and  are  fitted  with  brasses 
at  the  top  and  bottom,  like  any  ordinary  pillow  block.  Holes  are  left 
in  the  block  piece  for  the  main  columns  supporting  the  headstock 
to  pass  through,  which  are  fastened  by  cotters  secured  through  the 
casting.    This  arrangement  makes  a  very  stiff  and  strong  bed  plate. 

The  trunnion  blocks  are  sornetimes  separate,  bolted  down  on 
flanges  on  the  bed  plate;  and  the  main  columns  are  secured  to 


MARINE   ENGINES. 


355 


o 


Fig.  231. — Trunnion  Pillow  Block  cast  on  the  Bed  Plate. 
A,  Pillow  block  cast  on  frame.     B,  Cap  for  do.     c  c.  Bolts  for  do.     d  d.  Columns  for  supporting 


the  headstock. 


o 


o 


© 


Fig.  232. — Trunnion  Pillow  Block  separate, 

A,  Pillow  block.     B,  Cap  for  do.     c  c,  Bolts  for  do.     d.  Frame.     E  E,  Columns  for  supporting 

the  headstock. 


356 


MODERN   STEAM   PRACTICE. 


strongly  feathered  bosses,  and  the  necessary  flanges  are  provided 
for  bolting  the  bed  plate  to  the  condenser  casting.  The  frame 
should  be  no  larger  than  what  is  required  for  the  oscillation  of  the 
cylinder;  and  the  whole  is  bolted  down  on  the  top  of  wrought-iron 

bearers,  securely  riv- 
etted  to  the  vessel. 

The  Jieadstock  for 
the  crank  shaft  is  of 
cast  iron,  but  in  some 
instances,  where  light- 
ness is  a  desideratum, 
wrought  iron  has  been 
used.  For  small  en- 
gines the  headstock 
casting  is  generally 
of  an  T.  section,  but 
for  large  ones  a  box 
section  is  preferable. 
It  is  usually  cast  in 
two  halves,  bolted  at 
the  centre  on  the 
centre  line  of  paddle- 
wheel  ships,  each  half 
being  fitted  with  two 
pillow  blocks  cast  on, 
fitted  with  brasses  at 
the  top  and  bottom, 
and  secured  with  caps 
of  cast  iron,  having 
bolts  passing  down 
through  the  frame. 
Bosses  for  taking  the 
main  columns  are  cast 
along  with  the  head- 
stock.  These  columns  are  made  of  wrought  iron,  and  are  of  suffi- 
cient strength  to  receive  the  thrust  and  \Yeight  that  they  are  sub- 
jected to;  and  to  give  greater  rigidity  between  the  bed  plate  and 
the  headstock,  cross  stays  of  cast-iron  are  introduced  on  the  lar- 
board and  starboard  columns.  The  headstock  is  placed  between  the 
engme  beams  which  are  made  of  plate  iron  of  a  box  section  j  tliese 


Fig.  233. — Headstock. 
A  A,  Headstock  pillow  blocks.     B,  Cap  for  do.     c  C,  Holes  for  columns. 


MARINE   ENGINES. 


357 


beams  run  from  one  side  of  the  ship  to  the  other,  underneath  the 
deck,  and  the  lateral  strain  imparted  from  the  headstock  is  taken  on 
them,  wedge  pieces  being  introduced  between  them  and  the  cast- 
ing. As  the  strain  is  fore  and  aft,  these  engine  beams  should  be 
made  broad  in  the  direction  of  the  length  of  the  vessel.  The  hatch- 
way for  the  headstock  cuts  the  deck  in  two  at  the  middle  of  the 
vessel  where  strength  is  most  required,  and  breaks  the  continuity 
of  the  deck  stringers  running  fore  and  aft  on  the  top  of  the  deck 
beams  to  stiffen  the  vessel ;  it 
is  therefore  desirable  to  pass 
bolts  of  large  diameter  through 
the  engine  beams  and  head- 
stock,  by  which  the  frame  is 
firmly  secured  to  the  engine 
beams,  and  as  the  stringers  are 
rivetted  to  these  beams  the 
longitudinal  strength  is  main- 
tained. 

The  main  ^r^/z/^j' are  arranged 
in  the  usual  manner,  the  crank 
pins  being  firmly  secured  in 
the  inner  ones ;  while  the  lar- 
board and  starboard  cranks  are 
fitted  with  brass  bushes  for  the 
reception  of  the  ends  of  the 
pins,  in  which  they  work  quite 

loosely,  thus  preventing  any  undue  stress  on  the  main  shaft  in  a 
heavy  sea. 

Piston  ring  and  block. — We  now  come  to  notice  the  piston  of  the 
oscillating  engine,  which  is  fitted  with  a  ring  on  the  top,  termed  the 
junk  ring.  This  is  introduced  to  keep  the  packing  ring  in  its  place, 
and  is  bolted  down  with  screw  bolts,  the  brass  nuts  for  which  are  let 
into  recesses  left  in  the  body  of  the  piston ;  the  heads  of  the  bolts  are 
flush  with  the  top  of  the  junk  ring,  and  are  screwed  down  with  a  box 
key.  The  packing  ring  is  generally  in  one  piece;  after  it  is  turned  on 
the  rubbing  face  it  is  cut  at  one  part  and  sprung  into  its  place,  the 
cut  part  being  made  steam-tight  by  a  block  piece  of  brass,  with 
a  wrought-iron  guard  secured  to  the  spring  ring  at  one  end,  and 
moving  in  a  slot  at  the  other  end  on  a  guide  pin ;  the  brass  block 
is  also  Secured  to  the  ring  at  one  end,  and  left  loose  at  the  other. 


Fig.  234 
A  A,  Main  cranks. 


-Main  Cranks. 


B,  Crank  pin.     C,  Bush. 
D,  End  plate. 


358 


MODERN   STEAM   PRACTICE. 


The  use  of  this  guard  piece  is  to  allow  a  wedge  to  be  driven  between 
it  and  the  brass  block,  which  contracts  the  spring  ring;  the  piston 
is  then  placed  in  the  cylinder,  and  when  the 
wedge  is  removed  the  ring  expands  and  fits 
the  cylinder  exactly.  Curved  steel  springs  are 
then  inserted  between  the  piston  and  the  pack- 
ing ring  all  round;  thus  with  its  own  elasticity, 
and  with  the  aid  of  these  springs,  the  surfaces 
between  the  piston  and  cylinder  are  made  quite 
steam-tight.  All  the  parts  should  be  carefully 
turned,  and  the  surfaces  between  the  junk  ring 
and  the  piston  scraped ;  no  grinding  material 
should  be  used  to  make  this  joint  tight;  in  fact 
the  use  of  emery  for  making  steam  joints,  or 
for  getting  up  journals,  has  long  been  discarded, 
as  the  small  particles  of  grit  are  sometimes 
Fig.  235.  —  Piston  Ring  and  imbedded  in  the  metal,  and  soon  play  havoc 

Block  Piece.  11. 

With  rubbmg  surfaces. 

The  piston  rod  is  secured  by  a  nut,  sometimes 

placed  at  the  top,  in  other  cases  at  the  bottom, 

square    threads    for    which    are    cut    on    the 

rod.     The  nut  is  sometimes  flush  with  the  top  of  the  piston,  and  is 

screwed  into  the  recess  by  a  spanner,  fitted  with  a  pin  which  takes 


A,  Piston.  B,  Packing  ring. 
C,  Junk  ring.  D,  Bolt  and 
recessed  nut.  e.  Block  and 
guard. 


Fig.  236. — Top  Nut  for  Piston  Rod. 
A,  Piston.     B,  Cone  on  piston  rod.     c.  Nut. 


Fig.  237. — Bottom  Nut  for  Piston  R.od. 
A,  Piston.      B,  Cone,      c.  Nut.      d.  Pin. 


the  holes  drilled  in  the  top  surface  of  the  nut ;  a  better  plan,  how- 
ever, is  to  recess  the  nut  partly,  leaving  sufficient  projection  so  that 
it  can  be  tightened  up  with  an  ordinary  key.     Of  course  the  end  of 


MARINE    ENGINES. 


359 


the  piston  rod  must  be  turned  with  a  taper,  to  secure  a  perfect  fit 
between  the  piston  and  rod.  When  the  nut  is  placed  at  the  bottom 
of  the  piston  it  is  screwed  up  against  the  face  ring,  and  is  further 
secured  by  a  cotter  passing  through  the  rod ;  this  plan  is  gen- 
erally adopted  when  the  crosshead  for  the  crank  pin  forms  part  of 
the  rod.  Some  makers  leave  a  collar  for  bearing  on  the  top  of 
the  piston ;  and  with  a  solid  piston  rod  and  crosshead  the  glands 
require  to  be  cut.  The  collar,  however,  may  be  dispensed  with, 
as  a  plain  cone  is  quite  sufficient.  Recesses  must  be  left  in  the 
cover  and  the  bottom  of  the  cylinders  for  the  securing  nut  to  pass 
into. 

The  crossheads  for  the  piston  rod  are  of  various  forms.     Some  are 
forged  along  with  the  rod,  and  slotted   out  for  the  reception  of 


Fig.  238. — Piston  Rod  and  Crosshead  forged  on. 

A,  Crosshead.     B,  Cap.    c  c,  Bolts,     d,  Piston  rod. 
E,  Brasses. 


Fig.  239. — Piston  Rod  and  Socket  for  Crosshead. 

A,  Crosshead  of  brass.     B,  Cap.     c  C,  Bolts. 
D,  Socket  piece,     e.  Cotter. 


brasses,  which  are  secured  by  means  of  caps,  held  down  with  bolts 
passing  through  the  crosshead ;  others  are  forged  all  in  one  piece, 
and  are  bored  out  for  the  reception  of  the  rod,  which  is  held  in 
position  by  a  cotter;  others  again  have  a  T  piece  left  on  the  rod, 
or  a  T  bottom  piece  cottered  to  the  rod,  having  the  brasses  cast  to 
form  the  middle  part  of  the  crosshead,  on  the  top  of  which  is  placed 


360 


MODERN   STEAM   PRACTICE. 


the  cap  with  bolts  for  screwing  up  the  brasses.     An  oil  chamber 
should  be  forged  on  the  cap  and  then  bored  out,  or  a  seoarate  oil  cup 
fitted  with  a  siphon  wick,  for  lubricating 
the  crank  pin. 

The  air-pump  rod  crosshead  is  simi- 
larly constructed,  with  a  T  piece  formed 
on  the  rod,  having  brasses  and  cap  with 
bolts  passing  through.  The  bottom  part 
of  the  air-pump  rod  is  generally  left 


be 


^-^ 


J 


Fig.  240. — Air-pump  Rod  Crosshead. 

A,  Crosshead  of  brass.     B,  Cap.     c  C,  Bolts  and 
nuts.     D,  Rod. 


Fig.  241. — Air-pump  Rod,  bottom  end. 

A,  Rod.     B,  Inside  rod.     C,  Jib  and  cotter. 
D,  Bush. 


hollow,  and  is  fitted  with  a  steel  bar  inside,  so  as  to  be  able  to 
adjust  the  wear  of  the  brasses;  this  plan  is  of  course  only  adopted 
when  the  bottom  of  the  rod  is  attached  to  the  pin  on  the  crosshead 
placed  in  a  hollow  trunk. 

The  injection  valve  generally  adopted  is  the  simple  cone  plug  (Fig. 
242),  cast  hollow  and  fitted  with  a  stuffing  box  at  the  top,  with  a 
spindle  carried  up  and  supported  by  a  round  pillar,  on  the  top  of  which 
is  fitted  an  index ;  a  handle  is  fitted  to  the  spindle  for  actuating  the 
plug,  which  has  passages  in  connection  with  pipes  from  the  sea  for 
admitting  water  into  the  condenser.  Sometimes  flat  sluices  and 
gridiron  valves  are  adopted,  worked  by  levers  connected  to  the 
valve  spindles;  others  prefer  disc  valves  having  spindles  through 


MARINE   ENGINES. 


361 


the  centre  bosses  left  in  the  valve  seatings,  and  lifted  by  separate 
screwed  spindles  with  turn  wheels  and  handles;  and  some  small 

valves  of  this  type  are  lifted  by 
0  ->     levers,  the  short  end  of  the  lever 

working  in  a  slot  crosshead 
screwed  on  the  vertical  spindle.  The  pipe  placed 
inside  of  the  condenser,  in  connection  with  the 
injection  valve,  should  be  perforated  with  a  num- 
ber of  round  holes  or  slits,  so  placed  that  the 
water  is  distributed  or  showered  over  a  large  sur- 
face. Some  engineers  have  adopted  distributing" 
plates,  perforated  with  round  holes,  so  that  the 
water  falls  into  the  condenser  as  in  an  ordinary 
shower  bath.  We  prefer,  however,  the  perforated 
copper  pipe,  which  should  taper  to  a  smaller  dia- 
meter at  the  end  furthest  from  the  valve.  By  this 
means  the  water  is  more  equally  distributed ;  for 
were  the  pipe  to  be  made  of  equal  area  throughout 
the  pressure  would  decrease,  owing  to  the  water 
escaping  through  the  perforations,  but  when  the 
pipe  is  contracted  from  the  valve  to  the  end  which 
is  filled  up  then  the  pressure  is  maintained  more  equally  all 
along  its  length. 

The  Kingston  valve  (Fig.  243)  is  fitted  to  the  side  of  the  ship,  with 
a  cast-iron  piece  between  the  iron  plates  and  the  brass,  to  prevent 
corrosion  from  the  oxidation  caused  by  placing  brass  in  contact  with 
wrought  iron.  These  valves  are  fitted  to  the  vessel  before  it  is 
launched ;  they  consist  of  cone  valves  lifted  by  means  of  spindles, 
and  are  held  in  position  by  cotters  passing  through  the  spindles 
and  bearing  upon  columns  fixed  to  the  covers ;  the  spindles  pass 
through  these  covers,  and  are  made  tight  by  stuffing  boxes  and 
glands.  A  gridiron  is  fitted  at  the  bottom  of  the  case  or  pipe 
containing  the  valve,  to  prevent  extraneous  matter  entering  the 
condenser.  The  use  of  the  Kingston  valve  is  to  shut  off  the  sea 
water  in  the  event  of  any  of  the  pipes  which  supply  the  engines 
getting  damaged,  in  which  case,  if  some  contrivance  were  not 
adopted,  the  sea  water  would  rush  in  and  fill  the  engine  or  boiler 
room.  A  plug  valve  is  also  fitted  to  the  Kingston  valve,  so  as 
to  shut  off"  the  sea  water  effectually. 

The  blow-through  valve  (Fig.  244)  is  fitted  to  the  steam  pipe,  or 


Fig.  242.  —  Injection 
Plug  Tap. 

A,  Plug.      B,  Chest, 
c,  Gland  and  stuffing  box. 
D,  Standard.     E,  Handle. 


362 


MODERN   STEAM   PRACTICE. 


in  communication  with  it  and  the  condenser,  so  that  steam  from 
the  boiler  may  be  blown  through  the  condenser  and  also  into  the 


Fig.  243. — Kingston  Valve. 

A,  Valve  chest.     B,  Valve.     C,  Spindle. 
Cotter.     E,  Branch  piece  on  ship's  bottom. 


Fig.  244. — Blow-through  Valve. 

A,  Valve.     B,  Chest,     c,  Lifting  spindle. 
D,  Handle.     E,  Stud. 


cylinder,  warming  these  parts  and  expelling  the  air;  thus  by  turning 
on  the  injection  a  vacuum  is  formed  in  the  condenser,  before  the  steam 
from  the  valve  casing  is  admitted  into  the  cylinder. 
This  valve  is  a  spindle  one,  opened  with  a  lever 
handle,  and  is  held  down  by  the  steam  pressure  on 
the  top  side. 

The  snifting  valve  is  fitted  to  the  lowest  part  of 
the  condenser;  by  it  all  the  air  in  the  condenser 
escapes  in  the  process  of  blowing  through.  It  is 
a  plain  spindle  valve,  fitted  in  a  valve  chest;  the 
chest  and  valve  are  generally  of  brass,  or  a  cast- 
iron  chest  may  be  substituted,  with  a  brass  valve 
seating  let  into  it.  The  steam  in  blowing  through 
opens  the  valve,  and  all  the  air  is  driven  out;  but 
when  the  injection  is  turned  on  and  the  vacuum 


Fig.  245. — Snifting 
Valve. 

A,  Valve.     B,  Chest. 
C,  Set  screw. 


MARINE   ENGINES. 


Z^Z 


formed  it  instantly  closes,  and  is  secured  by  a  thumb  screw,  passing 
through  the  baffle  plate  which 
is  sometimes  fitted  for  throw- 
ing downwards  the  water  ex- 
pelled from  the  condenser. 

The  relief  valves,  placed  at 
the    top    and    bottom    of   the 
cylinder,  are  for  the   ejection 
of  the  water  collected  through 
priming  and  from  the  conden- 
sation of  the  steam.    They  are 
spindle   valves,  with  seats  of 
the  usual  form.    The  valve  for 
the  cylinder  cover  has  a  cap  on 
the  top,  on  which  are  placed 
the  spring  and  top  cap,  and  a 
set  screw  which  passes  through 
the  cover  required  to  prevent 
the  hot  water  from  scattering, 
provided  with  a  long  spindle,  on  the  top 
of  which  are  placed  the  cap  and  spring,  and 
which  is  screwed  down  by  a  screw  pass- 
ing through  a  bow  secured  to  the  valve 
casing,  the  baffle  plate  being  fitted  under 
the  bottom  cap.     In  some  examples  the 
valve  is  cast  with  a  long  spindle  on  the 
top  of  the  disc,  which  passes  through  a 
hollow  screw,  fitted  to  a  stud  placed  on 
the  cylinder;  between  this  stud  and  the 
valve  there  is  a  spiral  spring  with  a  cap  at 
the  top;  by  screwing  up  the  hollow  screw 
against  this  cap  the  spring  is  compressed 
to  any  desired  extent;  the  downward  pres- 
sure should  be  slightly  in  excess  of  the 
steam  pressure  on  the  valve,  so  that  when 
water  collects  in  the  cylinder  the  piston 
impinges  on  it  and  forces  it  through  the 
valve  into  the  bilges.    A  baffle  plate  must  ^'^'  '^'''''~  ^^^xxAIx. 
be  fitted  to  throw  the  hot  water  down-      a,  Vaive  and  spindie.   b,  chest. 
wards;  and  these  valves  should  be  placed    ^'^p""^"  ^ "B!rpiatc. ^'' """ 


Fig.  246. — Relief  Valve  on  Cover. 

A,  Valve.     B,  Cylinder  cover,     c,  Spring.     D,  Set  screw. 
E,  Baffle  cover. 


The  valve  for  the  cylinder  bottom  is 


364 


MODERN    STEAM   PRACTICE. 


at  the  back  of  the  cylinder  or  the  part  furthest  removed  from  the 
starting  platform,  to  prevent  the  engineer  from  getting  scalded  by 
the  steam  and  hot  water.  A  supplementary  plug  valve  is  also  fitted 
at  each  end  of  the  cylinder,  for  allowing  the  water  to  escape;  these 
valves  should  have  a  handle  common  to  both,  with  a  pipe  connec- 
tion for  passing  the  water  down  to  the  bilges ;  in  this  way  the  water 
can  be  blown  out  of  the  cylinder  independently  of  the  loaded  spring 
relief  valves,  which  are  only  brought  into  action  in  cases  of  heavy 
priming  or  other  serious  causes. 

The  expansio7i  valve,  when  one  is  fitted,  is  placed  on  the  top  of 
the  trunnion  pipes  at  the  side  of  the  vessel.  This  valve  is  usually 
of  the  double-beat  Cornish  type,  and  is  a  very  convenient  form, 
requiring  but  little  power  to  lift  it.  It  is  raised  by  a  variable  cam 
placed  on  the  paddle-wheel  shaft,  having  a  balanced  lever  with  rod 
passing  down  to  the  valve;  on  one  end  of  this  lever  there  is  a  small 
roller,  fitted  on  a  spindle  between  the  jaws  of  the  lever,  having  a 
screwed  spindle  so  arranged  that  it  can  be  turned  by  hand,  moving 
the  roller  to  suit  the  grade  of  the  expansion  required.  Sometimes, 
when  a  certain  grade  of  expansion  is  fixed  upon,  the  valve  can  be 
lifted  and  shut  by  a  rod  from  a  crank  pin  placed  on  a  wheel  driven 
off  another  wheel  on  the  paddle  shaft ;  by  moving  the  pin  in  a  slot 
any  amount  of  opening  by  valve  can  be  obtained,  the  rod  which 
connects  the  valve  to  the  pin  being  fitted 
with  a  right  and  left  hand  screw  for  adjust- 
ing the  length. 

The  tJirottle  valve  is  placed  between  the 
boiler  and  expansion  valve,  where  an  expan- 
sion valve  is  used;  but  where  it  is  not,  the 
throttle  valve  is  placed  on  the  top  of  the  el- 
bow trunnion  pipe  (Fig.  221).  The  valve  is  of 
the  butterfly  kind,  hung  equally  by  a  central 
spindle  passing  through  it,  fitted  with  levers 
and  rods  passing  along  to  the  starting  plat- 
form. The  seat  for  the  valve  consists  of  a 
short  flanged  pipe,  with  gland  and  stuffing 
box  for  making  the  spindle  steam  tight,  the 
other  end  of  the  spindle  having  a  reduced 
pin  let  into  a  hole  bored  in  the  casting. 
This  kind  of  valve  is  rather  troublesome  to  get  up,  so  as  to  properly 
fill  the  cyhnder  in  which  it  works ;  two  pins,  one  on  each  side,  should 


Fig.  248. — Lubricator  for  the 

Cylinder. 

A,  Oil  cup.    B,  Plug  tap.    c,  Handle. 


MARINE   ENGINES. 


3<55 


be  left  in  the  pattern,  placed  at  the  angle  the  valve  is  designed  for, 
and  the  valve  can  thus  be  turned  to  fit  the  seating  exactly. 

The  lubricating  cups  should  be  plain,  having  pipes  passing  down 
to  the  bearings,  fitted  with  siphon  wicks;  and  they  should  have 
covers  to  prevent  dirt  lodging  in  them.  Some  engineers  cast  the 
cups  on  the  various  parts,  while  others  prefer  light  cups  cast  in 
brass.  Fig.  248  shows  the  lubricator  cup  with  hollow  plug  fitted  to 
the  cylinder  cover  for  lubricating  the  piston. 

SLIDE-VALVE   GEAR. 


The  slide-valve  gear  for  the  oscillating  engine  dift'ers  so  much 
from  other  arrangements  that  it  requires  to  be  treated  somewhat  in 
detail.    The  mode  of  setting  out  this  valve  motion  has  been  already 


Fig.  249.— Slide  Valve.i 

A,  Slide  valve,     b.  Ring  for  taking  off  the  back  pressure,     c.  Valve  spindle.     D,  Valve  casing. 
E,  Valve-casing  cover.     F,  Cylinder. 

described,  and  although  the  various  plans  adopted  may  differ  in 
detail,  the  motion  produced  is  the  same  in"all.     Take,  for  example, 

*  In  this  section  the  various  figures  are  diminished  as  in  working  drawings  for  the 
workshop. 


366  MODERN    STEAM    PRACTICE. 

the  case  of  a  marine  engine  having  a  cylinder  4  feet  3  inches  in 
diameter,  and  length  of  stroke  4  feet.  The  short  D  slide  valve  is 
usually  adopted,  with  a  packing  ring  on  the  back  of  the  most 
improved  description.  The  ports  in  the  cylinder  are  not  nearly  so 
short  as  for  direct-acting  engines  having  the  multiple-ported  arrange- 
ment. There  is  a  port  at  the  top  and  bottom  for  the  steam,  in 
connection  with  one  half  of  the  passage  or  the  belt  cast  on  or  about 
the  centre  length  of  the  cylinder;  the  trunnion  or  pipe  on  which 
the  cylinder  oscillates  is  cast  on  the  centre  line  of  the  belt.  The 
outside  one,  or  the  one  nearest  the  ship's  side,  in  paddle-wheel 
engines,  is  for  the  steam,  and  the  one  nearest  the  centre  line  of  the 
vessel  is  for  the  exhaust  into  the  condenser,  being  in  communication 
with  the  central  ports  on  the  cylinder.  The  slide  valve  is  contained 
in  a  suitable  casing  bolted  on  the  cylinder,  and  provided  with  a 
movable  cover  at  the  back.  The  inside  face  is  planed  and  scraped 
perfectly  true,  so  that  the  slide  rings  are  steam-tight;  there  is  a 
small  hole  bored  in  the  back  of  the  valve  to  take  away  any  steam 
that  may  pass,  which  of  course  finds  its  way  into  the  condenser. 
There  are  generally  two  valves,  one  on  each  side  of  the  cylinder ; 
such  an  arrangement  not  only  reduces  the  size  of  the  ports,  but 
also  balances  the  cylinder  better.  When  one  valve  is  used,  a  coun- 
terpoise weight,  fixed  on  a  lever,  is  attached  to  the  cylinder,  and 
oscillates  with  it;  but  such  a  plan,  when  adopted  for  large  power,  is 
neither  so  neat  nor  so  compact  as  the  double  slide  valves,  although 
these  require  more  working  parts.  At  the  same  time,  when  two 
valves  are  used,  the  details  can  be  made  much  lighter,  as  the  area 
of  each  valve  is  much  less.  The  usual  mode  of  securing  the  valve 
spindle  to  the  valve  is  by  a  T  nut  let  into  the  valve,  having  a  cor- 
responding thread  on  the  valve  spindle,  with  a  jam  nut  to  secure  it 
in  its  position ;  and  in  other  arrangements  a  snug  is  cast  on  the 
valve,  with  a  hole  for  the  reception  of  the  valve  spindle,  having 
nuts  at  the  top  and  bottom.  The  centre  of  the  exhaust  port  and 
trunnion  may  be  taken  as  the  starting  point  for  setting  out  the 
valve  faces,  their  place  being  the  centre  line  of  oscillation  of  the 
cylinder.  The  opening  of  the  port  by  the  valve  is  found  by  the 
same  rule  as  that  used  in  other  arrangements.  Thus,  suppose  for 
the  cylinder  4  feet  3  inches  in  diameter,  with  stroke  of  4  feet,  the 
number  of  revolutions  is  28  =  224  feet  of  piston  speed  per  minute: 
we  have  therefore — 

2042  X  224  ,  „  .     , 

— =457  square  inches, 

1 0000 


MARINE   ENGINES. 


1^7 


which,  divided  by  2,  equals  22-8  square  inches  of  opening  of  port 
by  valve  for  each.  The  length  of  the  ports  is  found  by  dividing 
the  diameter  of  the  cylinder  by  3-4,  thus:  5 1-4-3-4=:  15  inches  long; 
and  22"8^i5  =  r52  inch,  the  opening  of  port  by  valve.  The 
combined  area  of  the  steam  ports  equals  ^gth,  and  that  of  the 
exhaust  xV^^^  of  the  area  of  the  cylinder:  thus — 


2042 
"25" 
2042 

"i3~ 


— ~  rr  81  "6  -=-  2  =  40'8  square  inches  in  steam  port; 
=  157-^2=  79  square  inches  in  exhaust  port. 


A  little  more  or  less  may  be  allowed  to  secure  even  dimensions. 

Throw  of  eccentric,  slide  gear,  &c. — The  oscillating  engine  differs 
from  all  others  in  having  reciprocating  pistons,  and  no  connecting 
rod,  the  piston  rod  and  crosshead  being  attached  directly  to  the 
crank  pin.  We  may,  however,  term  the 
distance  from  the  centre  of  oscillation  to 
the  crank  centre  the  length  of  the  con- 
necting rod,  as  from  A  to  B,  and  with  this 
length  as  a  radius,  from  the  point  B  sweep 
the  crank  path,  this  radius  is  the  length 
of  the  supposed  connecting  rod  when  the 
piston  is  at  half  stroke.  It  will  be  seen 
that  this  length  varies,  being  greatest 
when  the  rod  is  vertical,  the  piston  com- 
mencing the  IN  stroke,  and  rapidly  short- 
ening as  the  piston  descends,  until  the 
crank  pin  reaches  the  bottom  of  the  crank 
path,  when  the  length  will  be  simply  the 
vertical  height  from  B  to  OUT,  or  the  com- 
mencement of  the  up  stroke.  It  will  thus 
be  evident  that  the  radius  for  finding  the 
correct  angle  of  the  crank  for  cutting  off 
at  any  part  of  the  piston  stroke  varies. 
To  explain  this  more  fully:  Divide  the 
vertical  diameter  of  the  crank  path  from 
IN  to  OUT  into  eight  equal  parts,  fix  the 
point  of  the  compasses  at  the  point  of 
oscillation  as  at  B,  the  vertical  distance  to 
any  point  that  may  be  determined  on  for  cutting  off  the  steam,  say 
at  five-eighths  of  the  stroke  of  the  piston,  as  from  IN  to  OUT,  is  the 


Centre,  of 


Fig.  230.— Path  of  Crank. 


^68  MODERN   STEAM   PRACTICE. 

radius  that  determines  the  point  C  or  centre  of  crank  pin,  when  the 
steam  is  cut  off  at  five-eighths  of  the  piston  stroke.  Thus  the  versed 
sine  of  the  chord  of  the  arc  of  supply  to  the  cyHnder  can  be  found, 
namely,  D  E,  which  measures  nearly  lO  inches.  The  diameter  of 
the  circle  described  by  the  centre  of  the  eccentric  can  also  be  now 
found,  as  already  described  for  direct  motion;  but  as  the  lever  for 
taking  the  valve  spindle  may  be  shorter  than  the  one  for  the  slot 
link,  it  is  evident  that  the  eccentric  circle  must  have  a  greater 
diameter.  Supposing  this  is  the  arrangement  adopted,  and  the 
length  of  the  lever  for  the  valve  to  be  12  inches,  and  that  for  the 
slot  link  i^}4  inches  (those  lengths  can  be  only  determined  by 
laying  down  in  plan  the  valve  and  gear).  When  it  is  known  that 
the  versed  sine  of  the  chord  of  the  eccentric  circle  for  the  arc  of 
supply  is  the  full  opening  of  the  port  by  valve  minus  one-half  of 
the  lead,  we  have  the  following,  supposing  the  lead  to  be  ^th  part  of 
an  inch:  The  full  opening  of  the  port  by  valve  as  already  found  is 
1-5  inch  minus  yV  inch=r468  inch  as  the  versed  sine  of  the  chord 
of  the  arc  described  by  the  eccentric  circle  for  direct  motion.  The 
diameter  of  the  crank  circle  is  equal  to  48  inches,  and  the  versed 
sine  of  the  chord  of  arc  of  supply  is  10  inches.  We  have  therefore 
10  :  48  : :  r468  =  7"04  inches  diameter  of  eccentric  circle  for  direct 
motion,  or  for  levers  of  equal  length;  but  as  the  levers  for  working 
the  valve  are  of  unequal  length,  we  have  7*04  :  12::  i5'5=9"Oi 
inches  diameter  of  the  eccentric  path  or  full  travel  of  the  valve. 

Eccentric  and  hoop. — The  eccentric  is  cast  in  two  halves  and  bolted 
together,  for  the  convenience  of  taking  it  to  pieces  or  placing  it  on 
the  shaft.  Were  the  eccentric  placed  on  a  plain  shaft  at  the  end, 
with  nothing  to  interfere,  it  would  be  cast  all  in  one  piece;  but  as 
it  is  generally  placed  between  collars  turned  on  the  shaft,  at  the 
side  of  the  main  cranks,  the  ring  requires  to  be  in  two  halves.  The 
eccentric  sheave  revolves  freely  on  the  shaft,  and  has  a  catch  cast 
on  it,  with  a  corresponding  catch  fixed  to  the  shaft,  so  as  to  suit  the 
forward  and  backward  movements.  The  eccentric  sheave  is  also 
fitted  with  a  back  balance,  so  that  when  the  engine  is  reversed  by 
hand,  the  eccentric  rod  being  out  of  gear  and  the  sheave  being 
loose  on  the  shaft,  the  latter  is  perfectly  balanced,  and  prevented 
from  revolving  when  the  catch  is  not  driving  it.  This  is  most 
required  for  engines  of  great  power,  where  the  sheaves  being 
large  would  turn  rapidly  round,  and  being  met  by  the  catch  would 
impart  a  smart  blow,  tending  to  disarrange  the  gear.  For  small 
1- 


MARINE   ENGINES. 


369 


power  the  eccentric  is  fitted  with  a  brass  hoop,  bolted  together,  for 
taking  the  eccentric  rod,  and  large  engines  have  the  hoop  forged 


33/* 


Fig.  251.— Eccentric  and  Hoop. 
A,  Eccentric.     B,  Hoop  for  do.     c.  Catch.     D.  Balance. 

on  the  eccentric  rod,  and  lined  with  brass  pieces  at  intervals.  The 
siphon  cup  for  lubricating  the  sheave  is  either  cast  on  the  brass 
hoop,  or  is  separate,  as  when  the  hoop 
and  rod  are  forged  all  in  one  piece. 

Catch  on  shaft. — To  determine  the 
position  of  the  catch  on  the  shaft  to  suit 
the  forward  and  backward  movements; 
the  position  of  the  eccentric  centre  for 
the  forward  movement  being  directly- 
opposite  to  that  for  the  backward  move- 
ment. Draw  A  B,  the  line  of  crank,  and 
describe  the  circle  in  dotted  lines  equal 
to  the  throw  of  the  eccentric;  then  find 
the  versed  sine  of  the  chord  of  arc  of 
supply,  and  the  point  E  can  be  fixed, 
that  being  the  centre  of  the  eccentric 
for  the  forward  movement;  from  the  point  E  draw  a  line  perpendi- 
cular to  A  B,  and  produce  it  until  it  cut  the  eccentric  path  on  the 
opposite  side,  that  is  the  point  or  centre  of  the  eccentric  for  the 

24 


-f-Lrff- 


Fig.  252. — Catch  for  Eccentric  on  Shaft. 


370 


MODERN    STEAM   PRACTICE. 


i&y* 


T^ 


H 


■7^1, 


4 


Z'* 


A 


n 


backward  movement.  Draw  the  line  A  E,  which  is  the  centre  line 
of  the  catch  on  the  eccentric  sheave,  which  is  set  off  equally  on 
each  side  as  represented  in  section,  F  is  the  forward  end  of  catch, 
and  G  the  end  of  catch  for  the  backward  movement.  The  driving 
catch  on  the  shaft,  represented  in  black,  is  secured  by  bolts.  It  will 
be  seen  that  the  line  of  crank  is  so  much  in  advance  of  the  point 
on  the  end  of  the  catch  on  the  eccentric  at  G,  for  the  forward  move- 
ment; and  that  it  must  be  so  much  in  advance  of  the  point  F  for 
the  backward  movement.  Thus,  supposing  the  catch  on  the  eccen- 
tric were  stationary,  and  the  crank  free  to  go  backward  to  the  line 
represented  at  A  I,  it  would  travel  through  an  arc  the  distance  from 
H  to  G,  when  it  would  be  down,  and  the  catch  on  the  shaft  would 
be  moving  the  eccentric  the  contrary  way  from  the  direction  shown 
by  the  arrow,  and  the  crank  turning  the  paddle  wheel  astern.     It 

will  be  seen  that  the  catch 
on  the  eccentric  sheave  is 
placed  so  that  the  driving 
catch  embraces  one-half  of 
the  circumference  of  the 
shaft,  although  at  times  it 
'^p'may  be  less,  owing  to  the 
length  of  the  catch  on  the 
eccentric;  but  when  conve- 
nient this  position  of  the 
driving  catch  on  the  shaft  is 
to  be  preferred.  Thus,  when 
the  line  of  crank  A  B  is  in 
the  position  delineated,  it 
will  move  in  the  direction  of 
the  arrow  when  the  end  of 
the  catch  at  F  is  the  driver; 
but  when  the  end  of  the 
catch  at  H  becomes  the 
driver,  it  must  move  in  the 
contrary  direction.  The 
catch  on  the  eccentric  is  re- 
presented by  dotted  lines: 
the  line  of  crank  is  equidis- 
tant from  the  points  G  and  K.  When  the  engine  is  required  to 
move  either  forward  or  backward,  the  slide  valve  is  worked  by 


■3% 


^f 


'<N 


Fig.  253.  —  Eccentric  Rod  and  Socket. 
A,  Eccentric  rod.     B,  Socket  and  pin. 


MARINE   ENGINES. 


371 


hand,  and  the  eccentric  accommodates  itself  to  the  catch  fixed  on 
and  revolving  with  the  main  crank  shaft. 

Eccentric  rod  and  valve  gear. — The  eccentric  rod  in  this  example 
(Fig.  253)  is  a  plain  round  bar,  with  a  T  end  for  taking  the  eccentric 
strap;  the  end  for  taking  the  slot  link  passes  through  a  long  guiding 
piece,  oscillating  on  the  link  through  a  hole  having  a  brass  bush. 
Some — indeed  we  may  say  the  most — are  arranged  with  a  plain  gab 
end,  that  is  thrown  out  of  gear  when  the  engine  or  rather  the  valve  is 
worked  by  hand;  but 
in  this  arrangement 
the  rod  always  slides 
in  the  socket,  and  is 
thrown  into  gear  with 
a  plain  round  pin  pass- 
ing through  the  socket 
in  which  the  rod  slides. 
The  plain  gab  end, 
however,  is  usually 
considered  preferable 
for  large  engines.  The 
valve  rod  is  attached 
to  the  lug  cast  on  the 
valve  by  a  screw  cut 
on  the  end,  with  nuts 
on  the  top  and  bottom, 
which  are  screwed  up 
against  the  lug  on  the 
valve.  The  top  end 
has  a  slot  fitted  with 
a  sliding  block;  a  pin 
passes  through  the 
block,  and  is  secured 
through  the  eye  on  the 
rocking  lever.  The 
valve  rod  is  guided  at 
the  top  by  means  of 
a  bracket  fitted  to  the 
cylinder.  There  are 
two  rocking  levers  for  each  valve :  one  has  a  slide  block  working  in 
the  slot  link,  with  a  radius  suited  for  the  valve  gear  when  placed  at 


@ 

T  i <%—...>%. 


Fig.  254. — Valve  Rod  and  Guide.     Rocking  Levers  and  Stud, 

,  Valve  rod.      B,  Block  for  do.      c,  Guide  for  do.      D,  Lever  for 
valve.     E,  Lever  for  eccentric  rod.     F,  Stud  for  levers. 


372 


MODERN   STEAM   PRACTICE. 


half  Stroke ;  the  other  lever,  as  before  stated,  takes  the  slide  valve 
rod.  When  the  slide  is  at  half  stroke,  the  valve  covering  all  the  ports, 
the  distance  or  vertical  height  from  the  centre  of  oscillation  to  the 
slide  rod  pin  is  the  position  in  which  the  rocking  levers  are  level. 
The  sliding  blocks  on  the  slot  link  are  placed  slightly  apart,  and 
from  the  centre  of  the  trunnions  on  which  the  cylinder  oscillates  to 
the  centre  of  the  sliding  block  pins  is  the  radius  of  the  link.  The 
rocking  levers  for  taking  the  slot  link  and  valve  spindle  oscillate 

on  a  fixed  centre  or  pin  fitted  to  the 
cylinder,  the  rockmg  centres  on  levers 
being  bushed  with  brass.  This  bearing 
is  usually  in  the  form  of  a  pillow  block, 
bolted  to  a  bracket  cast  on  the  cylinder ; 
the  journal  and  covers  are  forged  all  in 
one  piece,  the  bfearing  being  in  the  middle 
with  the  levers  on  each  side.  The  radius 
of  the  slot  link,  as  before  stated,  is  the 
vertical  height  from  the  centre  of  the 
trunnions  to  the  centre  of  the  pins  on  the 
.  levers,  when  the  valve  is  placed  at  half 
stroke,  the  levers  lying  level.  The  ends 
of  the  slot  link  are  fitted  with  brass  guid- 
ing pieces,  one  of  the  guides  having  a 
rack  or  teeth  cast  on,  working  into  a 
pinion  fitted  to  the  starting-wheel  shaft. 
These  guides  are  hollowed  out  to  slide  on 
and  between  the  wrought-iron  columns 
for  supporting  the  crank-shaft  framing. 


s: 


2  5'A- 


s 


p 


Fig.  255. — Sector  and  Brasses. 

A,  Sector  and  rod.   B,  Hole  for  socket,    xhc  slot  link  is  Hkcwise  guldcd  at  the 

C,  Lifting  rack.  1,1  1  1      •  111  1 

top,  a  small  bracket  bemg  bolted  to  the 
headstock,  through  which  the  round  part  of  its  shank  slides.  The 
length  of  the  slot  link  must  be  determined  from  the  angle  of  oscilla- 
tion at  half  stroke,  and  the  necessary  clearance  for  the  sliding  blocks 
on  the  levers  must  also  be  allowed  for.  The  centre  of  oscillation  of 
the  socket  for  taking  the  eccentric  rod  has  a  brass  bush  fitted  to  the 
slot  link,  but  when  a  gab  end  is  used  a  plain  pin  is  simply  fastened 
to  the  link. 

Startiiig  gear. — For  working  the  slide  valve  by  hand,  in  engines 
of  small  power,  a  long  lever  handle  is  attached  to  the  wrought-iron 
columns ;  this  lever  is  fitted  with  a  link,  connected  to  the  slot  link 


MARINE  ENGINES. 


VJ\ 


by  means  of  a  pin ;  the  handle  vibrates  with  the  upward  and  down- 
ward motion  of  the  sector,  and  the  eccentric  rod,  fitted  with  a  gab, 
is  thrown  out  of  gear  by  a  small  lever  and  rod,  so  placed  that  it 
tends  to  keep  in  the  gab  when  in  gear,  and  prevents  it  falling  into 
gear  when  thrown  out  In  some  examples  springs  and  catches  are 
used  for  the  same  object.  Sometimes  the  lever  handle  is  adopted 
for  heavy  engines,  in  which  case  it  is  advisable  to  have  a  socket,  so 
as  to  detach  the  handle  when  the  engine  is  working;  but  the  better 


Fig.  256. — Starting  Gear. 
A,  Starting  wheel.     B,  Bracket,     c,  Pinion-rod  shaft.     D,  Column.     E,  Throw-out  handle. 

plan  is  to  have  this  part  of  the  gearing  arranged  so  as  to  be  able 
to  handle  the  valves  at  the  shortest  notice.  A  very  general  arrange- 
ment is  by  means  of  a  pinion,  working  in  a  rack  placed  on  one  of 
the  guides  that  \?,  bolted  to  the  sector  or  slot  link ;  on  the  other 
end  of  the  shaft  for  carrying  the  pinion  is  pjaced  the  starting  wheel. 
In  the  example  before  us,  the  starting  wheel  has  four  arms,  with  a 
central  boss,  which  is  keyed  on  the  shaft.  The  pinion  is  thrown 
in  and  out  of  gear  by  a  levei,  the  same  motion  disengaging  and 
putting  in  gear  the  eccentric  rod.    A  spring  detent  is  fitted  through 


374  MODERN   STEAM   PRACTICE. 

a  slot  on  the  throw-out  handle,  a  rod  being  attached  to  it  and  the 
pin  which  passes  through  the  socket  on  which  the  eccentric  rod 
slides.  This  arrangement  of  starting  gear  is  certainly  very  compact, 
although  for  heavy  engines  we  prefer  the  plain  gab  on  the  eccentric 
rod.  The  bracket  for  carrying  the  starting  wheel,  &c.,  for  small 
power,  is  generally  bolted  to  the  columns  for  carrying  the  head- 
stock. 

THE   LINK   MOTION. 

The  application  of  double  eccentrics  and  link  motion  to  the 
oscillating  engine  affects  but  little  the  general  arrangement  of  the 
valve  gear.  The  pin  on  the  sector  for  taking  the  gab  end  of  the 
eccentric  rod,  as  for  the  single -eccentric  arrangement,  is  used  for 
the  block  on  which  the  link  slides;  in  fact,  this  pin  and  block 
may  be  compared  to  the  pin  and  block  on  the  slide-valve  rod, 
in  the  direct  applications  of  the  link  motion  to  the  locomotive,  or  in 
horizontal  direct-acting  marine  engines.  Indeed,  the  oscillating 
engine  may  be  considered  a  direct-acting  engine,  whether  set  verti- 
cally, horizontally,  or  lying  at  an  angle ;  but  as  levers  are  interposed 
between  the  sector  and  valve  spindle,  the  motion  becomes  indirect. 

As  the  sector  always  moves  in  a  direct  line  similar  to  the  slide- 
valve  spindle  in  horizontal  arrangements,  and  as  the  pin  for  taking 
the  block  on  which  the  link  slides  is  fitted  directly  to  the  sector,  it 
only  remains  to  consider  the  application  of  the  double  eccentrics 
and  link  motion  from  this  point  to  the  centre  of  the  main  crank 
shaft.  Thus  when  the  levers  are  placed  horizontally  or  at  right 
angles  to  the  valve  spindle,  the  slide  valve  being  at  half  stroke, 
then  from  the  centre  of  the  pin  on  the  sector  to  the  centre  of  the 
main  crank  shaft  is  the  radius  for  describing  the  link,  to  which  the 
double  eccentrics  and  rods  are  fitted  in  the  usual  manner.  So  it 
will  be  understood  that  the  double  eccentrics,  keyed  fast  on  the 
crank  shaft,  having  rods  and  link  working  directly  in  a  line  with 
the  slot  link  or  sector  for  taking  the  levers  for  actuating  the  slide- 
valve  spindle,  simply  take  the  place  of  the  single-eccentric  rod  and 
gab  end,  having  means  of  throwing  out  and  also  of  actuating  the 
valve  by  hand,  to  suit  the  direction  required  for  the  forward  or 
backward  movements.  The  link,  however,  being  attached  to  eccen- 
trics for  both  the  forward  and  backward  motions,  the  combin- 
ation of  both  can  never  err  (with  proper  mechanism  for  moving  it 
on  the  block  which  oscillates  on  the  pin  attached  to  the  sector)  in 


MARINE   ENGINES.  .  375 

actuating  the  valves  as  required.  The  valve  mechanism  of  oscillating 
engines,  in  combination  with  the  link  motion,  is  beautifully  simple 
in  its  multiplicity  of  parts,  and  in  the  science  of  engine-building  it 
may  be  truthfully  regarded  as  the  perfection  of  valve  gearing.  It 
must  be  borne  in  mind  that,  although  the  positions  of  the  centres 
of  eccentrics  are  the  same  in  relation  to  the  centre  line  of  crank  as 
for  direct  motion,  yet  as  the  lever  for  taking  the  sector  must  move 
upwards,  to  depress  the  one  for  taking  the  valve,  the  positions  of 
the  eccentrics  on  the  eccentric  path  are  different,  that  for  the  oscil- 
lating engine  being  on  the  circumference  of  the  path  nearest  the 
crank  pin,  while  for  direct  action  the  centres  are  on  the  opposite 
circumference  of  the  eccentric  path.  The  mechanism  for  actuating 
the  links  acts  simultaneously,  and  a  very  general  arrangement  is  to 
have  a  thread  cut  on  the  shaft  for  taking  the  starting  handle,  fitted 
with  a  crosshead  working  in  suitable  guides,  the  centre  of  the  cross- 
head  being  bored  out  and  screwed  to  suit  the  thread  on  the  shaft. 
At  each  end  of  the  crosshead  there  is  a  part  turned  for  the  reception 
of  side  rods,  connecting  the  crosshead  with  the  main  links.  Thus 
by  turning  the  starting  wheel  in  either  direction,  the  crosshead,  side 
rods,  and  links  are  moved  in  the  direction  required.  The  bracket 
for  carrying  the  starting-wheel  shaft  and  for  guiding  the  crosshead 
is  cast  all  in  one  piece,  and  is  fitted  to  the  condenser  on  the  centre 
line  of  the  ship,  as  for  paddle-wheel  arrangements.  This  motion 
for  actuating  the  link  has  the  advantage  of  holding  it  in  any  positjon 
when  at  work,  without  the  aid  of  set  screws  or  any  other  appliance, 
which  is  a  great  desideratum  when  the  link  is  used  for  working 
expansively.  In  some  arrangements  the  starting  wheel  and  shaft 
actuate  a  crosshead,  generally  cast  in  brass,  on  which  lugs  are 
formed  for  the  reception  of  a  single  central  rod,  which  takes  a  lever 
on  a  cross  shaft,  vibrating  on  two  pillow  blocks.  On  each  end  of 
this  shaft  a  lever  is  fitted,  having  a  pin  and  rod  in  connection  with 
each  link ;  thus  motion  is  imparted,  and  the  link  put  in  forward  or 
backward  gear  as  required.  In  other  arrangements  the  crosshead 
and  guides  are  dispensed  with,  and  a  worm  wheel  substituted,  which 
is  placed  on  the  end  of  the  starting-wheel  shaft,  and  works  into  a 
pinion  placed  central  with  the  cross  shaft,  having  levers  and  rods 
in  connection  with  the  link,  as  already  described.  Sometimes  the 
bracket  for  carrying  the  starting- wheel  shaft  in  this  arrangement  • 
is  simply  a  pipe  bushed  at  each  end,  cast  along  with  the  hot  well, 
to  which  the  cross  shaft  has  pillow  blocks  also.     In  fact,  the  main 


3/6  ^  MODERN   STEAM   PRACTICE. 

thing  to  be  studied  in  the  mechanism  for  actuating  the  hnk  motion 
is  the  side  rods  for  taking  the  link:  let  them  be  of  sufficient  length, 
so  that  the  versed  sine  of  the  chord  of  the  arc  of  oscillation  may 
not  affect  the  link  in  relation  to  its  block;  because,  when  they  are 
made  too  short,  a  sliding  action  takes  place,  which  in  some  instances 
seriously  affects  the  proper  working  of  the  valve.  When  this  point 
is  duly  attended  to,  power  has  only  to  be  applied  to  the  lifting  or 
reversing  rods,  and  the  mechanism  for  applying  this  power  should 
in  all  cases  be  as  simple  as  possible.  For  small  engines,  a  cross 
shaft  with  pillow  blocks  cast  on  the  condenser,  and  having  levers 
and  rods  at  each  end,  actuated  by  a  plain  lever  handle,  and  with 
quadrant  and  catch  similar  to  the  locomotive  engine,  is  as  good  an 
arrangement  as  can  be  adopted. 

The  link  generally  used  is  of  the  solid  type,  slotted  to  receive 
the  block  on  the  sector,  all  of  which  are  made  to  the  proper  radius. 
The  lugs  for  taking  the  eccentric  rods  are  forged  on,  but  in  some 
instances  lugs  are  wanting,  and  the  rods  are  simply  attached  to  the 
ends  of  the  link.  The  former  is  the  better  arrangement,  as  the  pin 
on  the  eccentric  rod  is  nearly  in  a  line  with  the  pin  for  taking  the 
link  block,  thus  direct  motion  is  obtained;  while  in  the  latter 
arrangement,  the  eccentric  rod  pin  is  all  to  the  one  side,  and  in 
addition  a  larger  eccentric  sheave  is  required,  which  is  not  desirable. 
The  pin  on  the  link  for  taking  the  lifting  or  reversing  rods  is  placed 
midway  between  the  eccentric -rod  ends,  on  the  radius  line  of  the 
link,  and  it  is  forged  on  a  cross  bar  secured  to  the  link  by  rivets. 
In  some  cases  the  eccentric-rod  straps  are  forged  along  with  the  rods, 
having  a  lining  of  brass,  and  are  secured  on  the  eccentric  sheaves 
with  bolts  and  nuts ;  in  others  they  are  cast  in  brass,  and  the  rod 
attached  by  means  of  a  T  piece  forged  on  the  end,  with  suitable 
bolts  and  nuts,  lock  nuts,  and  securing  split  pins.  The  eccentric 
sheaves  are  cast  in  two  pieces,  accurately  fitted  together,  and  bolted 
similarly  to  the  sheaves  for  single-eccentric  arrangements;  this  is 
done  for  the  convenience  of  getting  them  on  or  off  the  shaft,  but 
where  circumstances  will  allow  of  it,  the  sheaves  are  better  cast  in 
one  piece,  which  simplifies  the  manufacture. 


MARINE   ENGINES.  377 

SPECIFIC   NOTICES   OF   MARINE   ENGINES. 

The  oscillating  engines  of  the  Great  Eastern  are  the  largest  yet 
made,  there  being  four  paddle  cylinders  of  74  inches  diameter  and 
14  feet  stroke;  the  diameter  of  the  paddle  wheels  is  58  feet. 

The  oscillating  engines  of  the  Clyde  river  steamer  Coluniba  are 
probably  the  largest  yet  used  in  any  river  steamer,  each  of  the 
two  cylinders  being  53  inches  in  diameter,  and  the  stroke  5  ft.  6  in. 

The  Lord  of  the  Isles,  another  large  Clyde  river  steamer,  has  two 
diagonal  oscillating  cylinders,  working  on  the  same  crank  pin.  The 
diameter  of  these  cylinders  is  46  inches,  with  a  5  feet  6  inches 
stroke.     These  steamers  are  fitted  with  surface  condensers. 

In  the  Post  Boy,  a  vessel  of  65  tons  and  20  horse-power,  built  on 
the  Clyde  in  1820,  the  late  Mr.  David  Napier  appears  to  have  tried 
a  surface  condenser,  consisting  of  a  series  of  small  copper  tubes 
through  which  the  steam  passed,  and  was  condensed  by  a  circulation 
of  cold  water  on  the  outside  of  the  tubes. 

The  Fairy  Queen,  the  first  iron  steamer  plying  on  the  Clyde^ 
launched  in  183 1,  had  an  oscillating  engine. 

The  steeple  engine,  first  introduced  on  the  Clyde  about  1836  by 
Mr.  David  Napier,  is  a  convenient  form  of  engine  for  river  boats. 
It  consists  essentially  in  an  overhung  triangular  frame  from  the 
crosshead,  on  which  hangs  the  connecting  rod.  This  frame  and 
rod  are  connected  with  the  piston  by  either  one  or  more  piston 
rods.  In  the  earlier  forms  one  rod  was  commonly  fixed  to  the 
lower  part  of  the  triangular  frame,  in  other  forms  two  and  often 
four  piston  rods  are  used. 

The  side-lever  engine  was  extensively  used  in  paddle-wheel 
steamers,  the  arrangement  being  very  much  that  of  an  inverted 
beam  engine. 

The  first  paddle  steamer  to  cross  the  Atlantic  from  Britain  was 
the  Siriiis,  built  at  Leith  in  1837,  and  engined  by  Messrs.  Wingate 
&  Co.  of  Glasgow.  The  Great  Western,  built  at  Bristol,  also  made 
the  passage,  the  two  arriving  in  New  York  about  the  same  time. 
The  Sirins  measured  178  feet  long  by  25  feet  8  in.  beam,  depth 
18  feet  3  in.,  and  was  450  tons  register.  She  was  fitted  with  two 
side-lever  engines  of  270  horse-power;  diameter  of  cylinder  60  in., 
stroke  6  feet;  paddle-wheels  24  feet  diameter  with  twenty-two 
floats,  and  appears  to  have  had  Hall's  surface  condensers. 

The  Cunard  steamer  Scotia,  the  last  great  ocean-going  paddle- 


37^  MODERN   STEAM    PRACTICE. 

wheel  vessel  built,  was  fitted  with  a  pair  of  side-lever  engines,  the 
diameter  of  cylinders  being  lOO  inches,  with  a  stroke  of  12  feet. 
The  diameter  of  paddle  wheels  was  40  feet. 

A  specimen  of  the  early  side-lever  engine  may  still  be  seen  placed 
on  a  pedestal  at  Dumbarton  pier  on  the  Clyde.  It  is  the  first  marine 
engine  made  in  1824  by  Mr.  Robert  Napier,  the  well-known  Clyde 
engineer,  for  the  steamer  Leven. 

Ti'iink  engines  were  introduced  by  Penn,  and  have  been  much 
used  in  H.M.  navy.  The  piston  rod  is  made  hollow,  and  the  connect- 
ing rod  being  centered  well  down  in  it  a  saving  of  room  is  effected. 

A  form  of  engine  now  common  on  Clyde  river  steamers  is  the 
,  diagonal  direct-acting.  In  these  engines  the  piston  rod  is  attached 
to  a  crosshead  working  in  slides,  and  from  this  crosshead  the  con- 
necting rod  stretches  to  the  crank  pin.  It  may  be  of  interest  here 
to  state  that  the  first  efiiciently  steam-propelled  vessel,  the  Char- 
lotte Dundas,  was  fitted  with  a  horizontal  direct-acting  engine;  this 
vessel  was  tried  successfully  on  the  Forth  and  Clyde  Canal  in  1802. 

In  many  of  the  earlier  steam  vessels,  from  the  Comet  downwards, 
spur-wheel  gearing  was  used  to  connect  the  engine  with  the  paddle 
shaft.  A  few  details  of  the  size  of  the  Comet  may  be  interesting. 
She  was  about  25  tons  burden,  and  was  built  for  Henry  Bell  in  1812 
by  Mr.  John  Wood  of  Port-Glasgow.  She  measured  42  feet  long, 
40  feet  keel,  and  i.i  feet  broad,  with  5  feet  6  in.  draft  of  water. 
The  engine,  made  by  John  Robertson  of  Glasgow,  was  a  condensing 
one  of  3  horse-power,  the  diameter  of  cylinder  being  1 1  inches,  and 
the  stroke  16  inches,  the  crank  working  below  the  cylinder;  the 
engine-shaft,  connected  with  a  fly-wheel,  is  said  to  have  been  of 
cast-iron,  and  3^  in.  square.  The  engine  was  fitted  on  board  before 
launching  afid  steam  raised.  At  first  the  Comet  was  fitted  with 
tw^o  pairs  of  paddles,  7  feet  diameter,  with  spur-wheels  of  3^  feet 
diameter;  but  soon  afterwards  she  was  lengthened  to  60  feet,  and 
a  new  engine  with  a  single  pair  of  paddles  substituted,  the  speed 
being  now  greatly  improved,  and  reaching  from  five  to  six  miles  an 
hour.  The  diameter  of  the  cylinder  is  stated  as  12^  inches  and 
the  horse-power  4. 

THE   PADDLE   WHEEL. 

The  paddle  wheels  now  in  use  are  generally  of  the  feathering  type, 
the  floats  entering  and  leaving  the  water  almost  vertically;  having  thus 
a  better  hold  of  the  water  than  the  fixed  floats,  which  enter  obliquely, 


MARINE   ENGINES. 


379 


and  whose  full  propelling  area  is  only  attained  when  the  arms  to 
which  they  are  bolted  are  vertical.  Thus  when  fixed  the  floats 
depress  the  water  on  entering,  and  tend  to  lift  it  when  leaving,  and 


f^      ID 


il 


&  2 

V  P3 


I*    o 


"  s 


to  obviate  this  difficulty  each  float  was  formerly  stepped,  or  made 
in  two  or  more  separate  pieces,  placed  one  before  another.  This 
plan,  however,  is  now  become  almost  obsolete;  the  feathering  floats, 
although  somewhat  complicated,  being  generally  adopted  for  all 


38o 


MODERN   STEAM   PRACTICE. 


fast  river  steamers,  and  the  screw  superseding  the  paddle  wheel 
almost  universally  for  ocean-going  steamers. 

^  To  understand  the  action  of  the  feathering  paddle  wheel  we  have 
to  consider  each  float  free  to  oscillate  on  pins  passing  through 
brackets  forged  on  the  paddle  arms ;  on  one  of  these  journals  an 
arm  is  fixed,  and  a  rod  for  each  float  is  attached  to  a  pin  on  the 

end  of  each  arm,  the  arms  being  all  con- 
nected to  a  strap  (Fig.  259),  which  is  free 
to  revolve  on  a  sheave  (Fig.  260)  placed 
eccentrically  with  the  main  shaft.    One 


Fig.  259. — Eccentric  Strap. 

A,  Strap  with  brass  lining  pieces.     B,  Seat  for 
driving  rod.     c  C,  Holes  for  radial  rods. 


Fig.  260. — Eccentric  Sheave  for  Paddle  Wheel. 

A,  Eccentric.       B,  Flange  for  bolting  it  to  the  ship's 

side. 


of  these  connecting  rods  is  the  driver,  and  is  firmly  secured  to 
the  eccentric  strap  in  a  way  similar  to  an  eccentric  rod  for  the 
valve   motion.     When   the   paddle  wheel   is   overhung,  with  one 

pillow  block  at  the  side  of  the 
vessel,  this  bearing  being  support- 
ed with  a  wrought -iron  bracket 
rivetted  to  the  side  of  the  ship,  the 
eccentric  sheave  is  secured  at  the 
end  of  the  pillow  block;  and  when 
the  paddle  wheel  is  supported  with 
an  outside  bearing  bolted  to  the 
sponsons,  the  eccentric  sheave  is 
bolted  to  the  side  of  the  ship  direct. 
In  setting  out  the  mechanism, 
we  consider  the  position  of  the 
driving  float,  as  we  may  term  it;  at  its  deepest  immersion  it  is 
quite  vertical,  and  as  the  rod  from  the  arm  that  is  fixed  on  the  float 
is  secured  to  the  eccentric  strap,  as  the  paddle  wheel  revolves  the 


Fig.  261. — Boss  for  Paddle-wheel  Arms. 
I  Boss.    B  B,  Seats  for  arms,    c,  Wrought-iron  ring. 


MARINE   ENGINES. 


381 


eccentric  ring  is  dragged  round,  and  the  driving  float  always  assumes 
that  vertical  position  at  the  deepest  immersion,  as  indeed  do  all  the 
other  floats,  the  only  difference  being  that  they  are  secured  to  pins 
on  the  eccentric  strap,  instead  of  being- firmly  bolted  to  it;  thus 
when  the  centre  line  of  the  eccentric  is  placed  on  a  level  line,  all 
the  floats  assume  different  angles,  but  at  the  same  time  each  float 
enters  the  water  in  a  slightly  oblique  direction,  and  leaves  it  verti- 
cally.    It  is  obvious  that  the  floats  must  not  be  placed  too  closely 


nu—  )!      ::                     ;  ;      i  ;   -rn 

/©^ 

[ 

•     ■: 

■     : 

■  i  i 

D 

0 

0 

0 

0 

0 

0 

.... 

0 
JP 

0 

Fig.  262. — Arm  and  Brackets  for  Floats. 

A,  Arm  and  bracket,     b.  Pin  and  brass  bush,     c,  Brass  bush,     d,  Bracket.     E,  Pin  and  brass 
bush.     F,  Bracket. 

together, — three  immersed  at  one  time  is  considered  sufficient;  if 
closer  packed  they  only  disturb  the  water  and  clog  the  action  of 
the  wheels.  Some  builders  prefer  simply  an  eccentric  or  a  circular 
sheave  (Figs.  264  and  265),  revolving  on  a  pin  firmly  secured  to  the 
sponsons,  and  fixed  aft  of  the  centre  of  the  paddle  shaft  in  a  hori- 
zontal line;  the  sheave  is  formed  of  two  flanges,  with  a  projecting 
piece  for  the  driving  arm,  and  pins  for  all  the  other  rods:  in  action 
this  form  is  similar  to  the  foregoing.  All  the  moving  joints  must 
be  bushed  with  brass,  both  on  the  pins  and  eyes,  to  preserve  and 
keep  fair  the  various  joints;  unless  this  is  properly  attended  to 
corrosion  would  set  in,  and  soon  destroy  the  feathering  paddle 
wheel. 

The  pillow  block  for  the  overhung  paddle  wheel  is  a  plain  casting 
fitted  with  a  cap,  the  bolts  for  securing  which  pass  down  through 


382 


MODERN   STEAM   PRACTICE. 


u 


.n 


Fig.  264. — Eccentric  and  Pin  for  Paddle  Wheel. 
A,  Eccentric.      B,  Part  for  driving  rod.      c.  Pin  for 
radial   rod.      D,   Bracket  bolted  to  the  sponson. 
E,  Pin  for  eccentric. 


Fig.  263. — Eccentric  rod,  &c.,  for  Floats. 
A,  Driving  or  eccentric  rod.     B,  Radial  rod. 


Fig.  265.— Overhung  Feathering  Paddle  Wheel.— A,  Boss,     b  b,  Arms,     c,  Rim.     d,  Float,     e,  Arm  for 
float.     F,  Driving  rod.     G  G,  Stays.     H,  Eccentric  and  pin  bolted  to  the  sponson.     1 1,  Brackets. 


MARINE   ENGINES. 


383 


the  bracket  fitted  to  the  side  of  the  ship ;  the  sole  of  the  block  is 
also  bolted  to  the  bracket,  as  shown  in  Fig.  266. 

In  some  ocean  steamers  the  paddle-wheel  shaft  was  arranged  so 
that  it  could  be  disconnected  from  the  engine  when  the  ship  was 
under  sail  alone.  The  simplest  plan  for  effecting  this  is  by  fitting, 
a  disc  on  the  end  of  the  shaft,  instead  of  the  usual  crank,  the  disc 
having  a  hoop  with  a  projecting 
lug  piece  for  taking  the  crank 
pin;  the  hoop  is  forged  all  in  one 
piece,  and  is  held  in  position  with 
a  fast-and-loose  collar  on  the 
round  disc;  the  grip  is  attained  by- 
friction  blocks,  or  wedges,  firmly 
screwed  between  the  disc  and  the 
hoop  on  the  circumferential  line, 
the  disc  being  keyed  to  the  shaft 
with  one  or  more  keys.  There- 
fore when  the  friction  blocks 
are  released,  the  shaft  and  disc 
revolve  independently  of  the 
engine,  the  motion  of  the  vessel 
through  the  water,  driven  by  the 
sails,  causing  the  paddle  wheels  to 
revolve.  In  this  way  the  progress 
of  the  vessel  is  not  impeded  so 
much  as  it  would  be  were  the  floats  stationary,  and  offering  a  great 
resistance  for  the  wind  to  overcome. 

The  paddle  wheel  of  a  ship  may  be  compared  to  an  ordinary 
carriage  wheel,  any  point  in  the  circumference  describing  a  cycloid 
curve.  The  circumferential  distance  a  carriage  wheel  travels  over 
is  an  exact  measure  of  the  distance  the  carriage  has  gone;  but  as 
the  paddle  wheel  acts  in  a  yielding  fluid,  the  distance  travelled 
over  by  it  is  not  an  exact  measure  of  the  vessel's  progress  through 
the  water.  The  difference  is  termed  the  slip  of  the  paddle,  and 
ranges  from  one-fourth  to  one-fifth  of  the  circumferential  distance 
the  paddle  wheel  has  gone  over,  which  of  course  must  be  measured 
on  the  mean  centre  of  propulsion  of  the  floats,  and  not  on  the 
extreme  diameter. 

The  reciprocating  parts  of  marine  engines  are  generally  balanced 
with  suitable  weights,  and  notwithstanding  that  the  cylinders  of 


Fig.  266.— Pillow  Block  for  Paddle  Wheel. 

A,  Pillow  Block.     B,  Cap  for  do.     c  c,  Holding-down 

bolts. 


384  MODERN    STEAM   PRACTICE. 

the  oscillating  engine  are  properly  balanced,  yet  the  pistons  and 
cranks  must  be  also  balanced  by  a  metal  float  fitted  on  each  paddle 
wheel,  although  that  is  partly  done  by  the  air-pump  bucket  and 
its  adjuncts,  the  crank  of  which  divides  the  path  of  the  main 
cranks  into  three  parts — that  is  to  say,  the  cylinder  cranks  being 
at  right  angles,  the  line  of  the  air-pump  crank  divides  the  longest 
circumferential  line  between  the  main  crank  pin  centres  into  equal 
parts. 

The  feathering  paddle  wheel  was  tried  at  various  times,  but  not 
with  much  success  till  about  the  year  1850.  Fixed  floats  were 
mostly  used  in  ocean-going  steamers,  being  considered  less  liable  to 
derangement. 

Two  pairs  of  paddle  wheels  have  been  proposed  to  be  used. 
The  Comet  had  at  first,  as  we  have  said  (p.  378),  two  pairs,  but 
these  were  removed,  and  a  single  pair  substituted.  Single  wheels 
at  the  stern  and  amidship,  as  in  twin-boat  arrangements,  have  also 
been  tried,  as  also  endless  chains  with  floats  attached,  passing  round 
a  couple  of  drums  driven  by  the  engine.  Iron  floats  have  some- 
times been  used  instead  of  wood  floats  in  paddle  wheels. 

Besides  the  screw  propeller,  to  be  afterwards  treated  of,  the 
propulsion  of  vessels  by  a  jet  of  water  has  been  tried.  This  con- 
trivance is  known  as  "  Ruthven's  Hydraulic  Propeller,"  and  consists 
of  a  turbine-like  wheel  driven  by  a  steam  engine.  The  water  is 
first  of  all  drawn  in  by  the  turbine,  and  then  driven  out  at  openings 
along  the  ship's  side  in  such  a  manner  as  to  keep  up  a  constant 
stream.  A  vessel  named  the  Nautilus,  furnished  with  Ruthven's 
propeller,  had  a  trial  trip  on  the  Thames  in  1868.  She  ran  at 
the  rate  of  135  and  7*2  miles  per  hour  with  and  against  the  tide 
respectively,  or  at  an  average  speed  of  I0'35  miles  per  hour;  and 
when  going  at  full  speed,  with  both  wind  and  tide  in  her  favour,  she 
was  made,  by  reversing  the  valves,  to  stop  dead  in  less  than  ten 
seconds  and  in  about  a  quarter  of  her  length.  The  plan  has  also 
been  tried  in  H.M.  iron-clad  gun-boat  Waterwitch,  of  about  780  tons, 
with  some  success.  It  has  also  been  tried  in  the  United  States  of 
America,  but  without  commending  itself  as  against  either  the 
paddle  or  the  screw. 

It  should  be  noted  in  all  questions  of  propulsion  that  the  principle 
involved  is  the  putting  in  motion  of  a  quantity  of  water  in  a  back- 
ward direction,  the  reaction  from  which  action  is  the  propulsive 
effect.     Professor  Rankine  sives  the  following-  rule  for  the  thrust 


MARINE  ENGINES.  385 

of  a  propeller,  whether  paddle,  screw,  or  jet,  in  lbs. : — "  Multiply- 
together  the  transverse  sectional  area  in  square  feet  of  the  stream 
driven  astern  by  the  propeller;  the  speed  of  that  stream  relatively 
to  the  ship,  in  knots;  the  real  slip,  or  part  of  that  speed,  which  is 
impressed  on  that  stream  by  the  propeller,  also  in  knots;  and  the 
constant  5 '66  for  sea  water  and  5 '5  for  fresh  water." 


HORIZONTAL   DIRECT-ACTING  AND   RETURN 
CONNECTING-ROD   ENGINES. 

In  these  engines  the  cylinders  are  placed  side  by  side,  as  in  the 
locomotive  engine,  and  the  steam  valves  are  worked  directly  off 
the  cranked  shaft  by  double  eccentrics  and  link  motion.  The. 
condensers  are  placed  on  the  opposite  side  of  the  shaft  for  return 
connecting-rod  engines;  they  are  fitted  with  guides  for  the  cross- 
heads  ;  the  piston  rods  are  secured  to  arms  forged  on  the  crosshead, 
and  are  so  arranged  for  the  rods  crossing  the  cranked  shaft,  one  above 
and  the  other  under  the  shaft.  The  connecting  rod  by  this  arrange- 
ment is  not  in  a  direct  line  with  the  piston  rods,  but  goes  backwards, 
while  the  piston  rods  are  connecting  to  the  piston  in  a  forward  line 
crossing  the  main  shaft  of  the  engine. 

The  distance  between  the  centres  of  the  cylinders  in  these  engines 

is  regulated  by  the  arrangement  of  the  air  pumps  and  valves.    When 

the  air  pumps  are  close  together  on  each  side  of  the  centre  frame, 

the  distance  between  the  centres  is  greater  than  when  the  air  pumps 

and  adjuncts  are  placed  further  apart,  close  to  the  outer  frames; 

however,  it  is  not  a  good  plan  to  contract  the  water  passages  in 

connection  with  the  air  pumps  and  condenser  to  gain  a  few  inches 

between  the  centres  of  the  cylinders.     Steam  jackets  are  generally 

used,  cast  along  with  the  cylinder;  the  fronts  and  cylinder  covers 

are  also  made  double,  so  that  the  steam  from  the   boiler  freely 

circulates  all  round  the  cylinder,  and  the  full  pressure  is  better 

maintained  on  the  piston,  a  higher  indicated  measure  being  given  out 

than  by  an  unjacketed  cylinder.     To  prevent  condensation  in  the 

steam  casing  the  outside  of  the  cylinder  should  be  covered  with 

felt,  and  then  overlaid  with  lagging  or  narrow  strips  of  wood,  which 

are  secured  to  wooden  hoops,  bolted  to  the  strengthening  ribs  left 

in  the  casting.    The  passages  for  the  steam  and  exhaust  are  arranged 

25 


386 


MODERN   STEAM   PRACTICE. 


for  double-ported  valves,  that  is  to  say,  there  are  two  steam 
passages  at  each  end,  and  one  central  passage,  in  communication 
with  the  condenser.  The  joints  should  be  placed  metal  to  metal, 
all  planed  or  surfaced  in  the  boring  lathe,  and  the  rubbing  surfaces 

Figs.  267-268. — Cylinder.' 


for  the  slide  valve  should  also  be  carefully 
planed  as  smooth  as  possible,  and  then 
scraped  to  a  face  plate,  before  the  slide 
valve  is  fitted,  which  should  also  be  care- 
fully faced  on  the  plate,  and  thus  both 
surfaces  will  only  require  a  finishing  touch. 
All  the  other  joints  are  made  steam-tight 
by  interposing  a  thin  coating  of  red  lead. 
The  joints  being  thus  metallic,  the  work- 
ing of  the  engine  has  but  little  tendency 
to  loosen  them,  which  might  otherwise 
happen  were  an  elastic  joint  adopted.  On 
the  front  end  of  the  cylinder  a  central  manhole  must  be  left,  for  the 
boring  bar  to  pass  through;  with  single  piston  rods  there  is  a  small 
cover  with  stuffing  box  and  gland,  but  with  double  or  more  piston 
rods  a  plain  cover  is  fitted ;  holes  are  also  left  in  the  front  end  of  the 
cylinder  for  the  air-pump  rod,  with  suitable  glands  and  bushes,  and  a 
hole  at  the  bottom  for  the  relief  valve;  narrow  fitting  strips  should 
be  left  at  those  parts  where  the  main  framing  abuts  against  the 
other  fittings.  The  cylinders  are  bolted  together,  with  flanges  placed 
between  them,  having  narrow  fitting  strips  all  round,  which  are  care- 
fully planed ;  all  the  holes  should  be  drilled,  and  rimed  out  to  make 


*  A,  Cylinder,     b.  Annular  steam  space,     c  c.  Steam  ports,     d,  Exhaust  port,     e.  Exhaust  branch. 
F  F,  Piston-rod  glands,     g,  Cover  for  hole  for  boring  bar. 


MARINE   ENGINES. 


3^7 


them  quite  fair^;  by  this  means  the  turned  bolts  fit  the  holes 
exactly,  and  good  firm  work  is  obtained.  The  flanges  at  the  top 
and  bottom  are  planed,  and  the  latter  are  cast  along  with  the 
flanges  for  bolting  down  the  cylinder  on  the  keelsons.  Raised  parts 
should  be  left  on  the  casting  at  all  the  places  where  the  bolts  are 
arranged ;  in  this  way  an  even  face  is  easily  made  for  screwing  the 
nuts  up  against,  which  helps  to  secure  first-rate  work. 

The  cylinder  cover  should  be  a  deep  and  strongly- ribbed  casting, 
fitted  with  a  central  manhole  door,  through  which  the  bolts  of  the 
piston  and  piston  rods  may  be  inspected  without  requiring  to  break 
the  joint  of  the  cover,  which  is  a  somewhat  difficult  task  at  sea, 


A  i         ^ 


Fig.  269. — Cylinder  Covers. 

A  A,  Covers.     B  B,  Manhole  covers,     c  c,  Recesses  for  piston-rod  nuts.     D,  Recess  for  air-pump  rod  nut. 
E,  Hole  for  relief.     F,  Recess  for  single  piston-rod  nut. 

more  especially  with  large  and  heavy  covers.  The  number  of  bolts 
should  be  carefully  calculated,  so  as  not  to  have  a  great  prepon- 
derance of  strength  in  that  part,  for  in  the  event  of  the  cover 
receiving  a  violent  blow  from  the  piston  striking  against  water  in 
the  cylinder  due  to  violent  priming,  when  the  flanges  in  the  cylinder 


388 


MODERN    STEAM   PRACTICE. 


and  cover  are  properly  proportioned  the  bolts  should  rather  give 
than  a  breakage  occur.  A  hole  is  left  at  the  bottom  of  the  cover 
for  the  relief  valve,  similar  to  that  in  the  front  of  the  cylinder. 

The  stiLffing  boxes  for  the  piston  rods  are  fitted  with  a  lantern  or 
hollow  distance  piece,  with  an  extra  light  gland  placed  on  the  main 
one,  the  stuffing  box  of  which  is  packed  in  the  usual  manner.  The 
lantern  brass  is  placed  in  the  outside 
stuffing  box,  and  then  a  gasket  of  hemp  or 
other  packing  is  placed  on  the  back  of  it, 
and  screwed  up  with  the  light  gland.  The 
use  of  this  lantern  brass  is  to  leave  a  space 
all  round  the  piston  rod  for  containing  the 
lubricating  oil ;  the  piston  rod  has  thus  a 
ring  of  oil  all  round,  which  is  kept  in  the 
space  by  the  hemp  packing,  and  pre- 
vented from  dropping  down  and  running 
to  waste.  The  main  glands  are  gener- 
ally screwed  down  with  plain  bolts  and  a,  Packing  space.  B.Gland.  c,011  space. 
,  .  -  .  .  .    ,      D,  Gland.    E,  Bush.    F,  Cylinder  cover. 

nuts;    but    m    fast-gomg    engmes   a  risk 

attends  this  method,  as  the  gland  is  liable  to  be  pressed  against  the 

side  of  the  rod,  and  thereby  to  throw  an  undue  strain  on  the  piston 


Fig.  270. — Piston-rod  Gland  witk 
Lantern  Brass. 


Fig.  271. — Piston-rod  Gland  with  Adjusting  Gear. 
A,  Packing  space.     B,  Gland.     CC,  Worm  wheels  and  pinions.     D,  Spindle. 

rods.  In  order  to  effect  a  parallel  strain  on  the  packing,  as  well  as 
to  be  able  to  tighten  up  the  gland  when  the  engines  are  in  motion, 
two  large  bolts  are  used,  with  worm  wheels  and  pinions  on  each, 
and  a  spindle  connecting  them ;  thus  by  one  movement  the  gland 
can  be  tightened  up  in  a  parallel  manner.     In  some  engines  of  the 


MARINE   ENGINES.  389 

direct-acting  type  the  packing  gland  for  the  piston  rod  is  recessed 
into  the  end  of  the  cyHnder,  the  end  being  curved,  as  well  as  the 
piston  and  cover :  by  this  means  a  slight  gain  is  obtained  in  the 
length  of  the  main  connecting  rod,  but  otherwise  it  affords  no 
advantage,  and  the  patterns  are  more  difficult  to  make. 

The  exhaust  pipe  in  communication  with  the  condenser  is  cast 
along  with  the  cylinder,  and  can  be  made  of  any  required  shape, 
provided  the  area  is  sufficient.  The  circular  shape,  however,  is  the 
strongest  and  best  for  that  part  of  the  exhaust  pipe  which  joins  the 
thin  copper  pipe  leading  to  the  condenser,  as  the  latter  pipe  forms 
really  part  of  the  condenser,  and  unless  it  were  made  circular  it 
would  collapse  with  the  atmospheric  pressure.  The  ends  and  covers 
of  the  cylinder  must  be  strongly  ribbed  in  the  casting  with  feathers 
radiating  from  the  centre ;  from  this  not  being  properly  attended 
to,  the  pulsation  of  the  cast  iron  in  some  covers  is  quite  visible  at 
each  stroke  of  the  piston.  This  bending  and  unbending  of  the 
metal  of  course  deteriorates  its  molecular  particles,  and  when  any 
undue  strain  comes  upon  the  cover  from  excessive  priming,  there  is 
danger  of  its  becoming  fractured,  or  indeed  of  being  blown  out 
altogether,  as  has  happened  to  many  covers  and  ends.  A  small 
branch  pipe  should  be  cast  on  the  exhaust  pipe,  for  the  blow- 
through  valve,  which  is  connected  to  the  valve  casing  or  the  steam 
pipe,  according  to  the  locality  of  other  details.  Small  bosses  should 
also  be  cast  on  the  bottom  of  the  cylinder  at  each  end,  to  which 
small  plug  valves  are  fixed  for  allowing  the  water  to  escape  out  of 
the  cylinder  before  starting;  these  valves  are  connected  together 
with  levers  and  rods,  one  handle  serving  to  open  them  both.  All 
small  fittings  that  are  intended  to  be  fixed  on  the  cylinder  should 
have  facing  strips  cast  on,  which  tends  to  lessen  the  labour  in  the 
workshop.  To  effect  this  important  object  more  completely,  some 
makers  have  cast  the  cylinders  together,  but  the  risk  in  this  method 
is  considerable.  We  have  seen  castings  of  this  kind  that  looked 
sound,  and  one  of  the  cylinders  on  being  bored  out  presented  a 
good  surface,  but  the  other  was  quite  porous  and  full  of  blown 
holes;  both  of  the  cylinders  of  course  requiring  to  be  broken  up  as 
useless.  This  fact  may  deter  many  from  trying  such  a  plan,  at 
least  for  large  cylinders,  yet  for  small  ones  the  advantages  are 
great,  and  the  risk  proportionately  less.  Care  should  be  taken, 
however,  that  the  metal  be  neither  too  soft  nor  too  hard,  more 
especially  the  latter,  as  extremely  hard  castings  should  be  avoided, 


390 


MODERN   STEAM    PRACTICE. 


particularly  for  great  steam  pressure.  Many  cylinders  cast  too 
hard  have  cracked  in  all  directions  after  being  but  a  very  short 
time  in  use,  owing,  it  is  considered,  to  the  unequal  expansion  of 
the  metal.  The  core  of  the  casting  has  been  removed  in  the 
moulding  pit  to  cool  the  inside  of  the  cylinder,  which  makes 
this  portion  harder  than  the  outside  portions,  and  strains  the  metal 
forming  the  whole  casting,  rendering  it  brittle,  and  very  liable  to 
give  way  under  steam  pressure  in  those  parts  where  the  expansion 
of  the  metal  is  the  greatest.  Good  metal  only  should  be  eniployed, 
and  the  casting  allowed  to  cool  slowly. 

The  slide  valve  is  a  very  important  detail,  and  is  generally  of  the 
double-ported  type,  although  treble  ports  are  sometimes  introduced. 
Considering  the  great  size  that  is  required  for  direct-acting  engines, 
this  valve  should  be  Avell  proportioned,  and  all  its  gear  of  a  strong 
and  substantial  make.  Some  engineers  still  prefer  valve  facings  of 
hard  brass,  secured  to  the  cylinder  face  by  screwed  pins  rivetted 
over;  and  even  steel  facings  have  been  successfully  used  for  high- 
pressure   marine   engines.      There   can    be   no   doubt   that   when 


'/.■>,mlm>>,,/m!,/m'^\^.^rf/;Mm//w,w/w,•^^^^ 


^ 


Fig.  272. — Slide  Valve,  with  rod  passing  through  it. 
A,  Slide  valve,     b,  Valve  rod.     c  c.  Steam  ports.     D,  Exhaust  port,     e,  Guide  for  valve  rod. 

the  slide  valve  is  placed  on  its  edge,  cast-iron  surfaces  are  found 
to  answer,  when  properly  provided  with  means  for  running  off 
the  water  that  collects  in  the  valve  casing  when  the  engines 
are  standing,  still,  as  the  moisture  must  impair  the  cast-iron 
surfaces,  and  the  slightest  unevenness  of  the  facings  will  pass 
steam,  it  is  perhaps  advisable  in  some  cases  to  use  brass  sur- 
faces. Perfection  in  detail  is  doubtless  the  main  thing  to  be 
studied,  eveii  although  it  may  entail  at  first  considerable  cost  in 
construction.  Various  methods  are  adopted  for  securing  the  valve 
rod  to  the  valve.  In  some  engines  the  rod  passes  through  a  tube 
cast  along  with  the  valve,  and  is  secured  by  a  collar  at  one  end  of 
the  rod  and  two  nuts  at  the  other  end;  in  others  again  the  valve 


MARINE   ENGINES. 


391 


rod  is  screwed  (Fig.  272),  having  a  raised  screwed  part  at  both  ends 
and  double  nuts ;  by  this  means  the  valve  can  be  very  accurately 
set  at  any  time.     The  hole  through  the  valve  should  be  slightly 


.  a 

o 
4-;   '^ 


•a  -5 


>  > 


oblong,  to  allow  for  the  wear  and  close  contact  between  the  faces  of 
the  valve  and  cylinder.  The  valve  rod,  in  some  examples,  is  guided 
at  the  end  through  a  hollow  brass  pipe,  or  a  stuffing  box  and  gland, 
similar  to  the  front  end.  In  other  arrangements  the  end  of  the 
valve  spindle  is  screwed  into  a  nut  recessed  in  the  valve  casing ;  the 
thrust  is  taken  on  the  end  of^  the  nut,  and  the  pull  on  projections 


392 


MODERN   STEAM   PRACTICK 


formed  on  the  nut  of  a  T  shape;  a  thin  jam  nut  is  fitted,  so  as 
thoroughly  to  bind  the  rod  and  nut  together:  both  of  these  nuts 
should  be  made  of  steel,  and  case-hardened.  Another  method  of 
securing  the  valve  rod  is  by  a  cotter  passing  through  a  boss  cast 
on  the  valve,  the  cotter  being  fitted  with  a  split  pin  to  prevent  it 
shaking  loose.  With  the  view  of  relieving  the  rod  and  adjuncts 
from  the  severe  strain  caused  by  the  steam  acting  on  the  back  of  the 
valve,  packing  rings  are  fitted  to  the  valve,  or  rings  of  metal  pressed 
up  against  it ;  in  the  former  case  the  ring  is  recessed  in  the  valve, 
and  pressed  up  with  springs  against  a  planed  piece  on  the  valve- 
casing  cover ;  in  the  latter,  the  ring  is  recessed  in  the  valve-casing 
cover,  and  pressed  up  with  set  screws  against  the  valve.  The 
object  of  both  of  these  plans  is  to  obtain  a  large  area  on  the  back 
of  the  valve  from  which  the  steam  in  the  casing  is  excluded  by 
means  of  the  metallic  rings,  which  of  course  do  not  leave  such 
large  surfaces  for  the  steam  pressure  to  act  upon.  This  hollow 
space  is  sometimes  fitted  with  a  small  pipe  in  communication  with 
the  condenser;  thus  the  valve  is  partly  drawn  from  the  face  as  it 
were  by  the  vacuum. 

The  valve  casing  is  a  separate  open  frame, 
cast  with  flanges  for  securing  it  to  the  cylinder. 
It  is  very  rarely  cast  along  with  the  cylinder, 
at  least  for  heavy  engines ;  although  for  engines 
of  small  power  this  plan  may  be  advantage- 
ously adopted.  The  casing  cover  is  generally 
cast  with  a  recessed  ring,  and  bosses  for 
springs,  which  are  accurately  turned  out  for 
the  reception  of  the  packing  rings  and  springs;  pig. 
it  is  of  a  curved    shape,  quite  plain  on    the 

.  ,  ,  11        -1  1        1  .^  •        •  1  1   •    1      A,  Slide  valve.      B  B,  Rings  for 

outside,  and  well  ribbed  on  the  inside,  which  ^^^j^g  ^^  ^i^^  ^ack  pressure, 
prevents  the  dust  from  lodging,  and  the  plain    c,  spring,     d.  Set  screw. 

^  .  .  E,  Valve-casuig  cover. 

exterior  surface  is  easily  wiped  down, — an  im- 
portant consideration  in  all  the  parts  of  a  marine  engine,  as  that 
operation  can  only  be  properly  attended  to  when  the  vessel  is  in  port. 
A  snug  should  be  cast  along  with  the  cover,  having  a  hole  bored  in 
it  for  a  wrought-iron  shackle  and  pin,  to  which  blocks  and  tackle 
can  be  secured  when  taking  off  and  putting  on  the  heavy  covers. 

The  branch  for  the  steam  pipe  is  generally  placed  at  the  back 
of  the  valve  casing,  and  is  cast  along  with  it,  the  flanges  looking 
towards  each  other  from  cylinder  to  cylinder.     At  one  end  there 


274. —  Spring  and  Packing 
for  Slide  Valve. 


MARINE   ENGINES. 


393 


is  a  stuffing  box  and  gland,  and  at  the  other  end  the  copper  pipe 
is  bolted  to  a  plain  flange;  while  the  part  in  the  gland  is  quite 
loose,  expanding  and  contracting  with  the  varying  pressure. 

Eccentric  and  link  motion. — Various  descriptions  of  valve  gear 
are  in  use,  but  the  one  generally  adopted  is  the  double  eccentrics  and 
link  motion.  This  is  only  introduced  as  a  sure  means  of  handling 
the  engines,  and  is  but  rarely  used  for  working  expansively,  as  in  the 
locomotive,  for  the  obvious  reason  that  were  the  slide  valve  travel- 


Fig.  275. — Eccentric  Sheaves. 
A,  Eccentric.     BB,  Keys,     c.  Bolt  for 
eccentric. 


Fig.  276. — Eccentric  Strap  and  Rod. 
A,  Eccentric  strap.     B,  Rod.      c,  Lubricator  cup. 
and  pin  for  link. 


D,  Jaw 


ling  only  a  small  portion  of  its  stroke,  and  kept  running  for  weeks 
in  this  reduced  grade,  a  groove  would  be  formed  on  the  cylinder 
face,  which  would  pass  steam  into  the  condenser  when  the  valve  or 
link  was  put  in  full  gear,  and  so  impair  the  vacuum;  and  it  thus 
becomes  imperative  to  have  a  separate  expansion  valve.  In  the 
example  in  Fig.  275  the  eccentrics  are  cast  in  two  halves  and 
secured  with  bolts  and  nuts,  in  other  examples  they  are  cast  solid; 
in  both  cases  they  are  firmly  secured  to  the  shaft  by  keys,  as  shown. 


394 


MODERN   STEAM   PRACTICE. 


The  eccentric  strap  (Fig.  276)  is  of  brass,  having  a  wrought-iron  rod 
with  T-piece  forged  on  one  end,  secured  to  the  strap  by  bolts  and 
nuts,  the  heads  of  the  bolts  being  re- 
cessed in  the  strap ;  on  the  other  end  a 
jaw  is  formed  for  taking  the  link.  The 
latter  has  eyes  forged  on  and  fitted 
with  brasses  and  set  screws  for  adjust- 
ing the  wear  on  the  eccentric -rod 
pins;  the  suspending  pin  for  the  link 
is  formed  with  a  palm,  which  is  se- 
curely rivetted  to  the  link. 

The  various  arrangements  of  valve 
mechanism  have  been  treated  more 
fully  in  a  former  part  of  this  Work  (see 
page  1 10). 

When  gridiron  expansion  valves  are 
used,  the  seating  on  the  valve  face  is 
cast  along  with  the  casing,  making  a  very  compact  arrangement. 
The  valve  in  Fig.  278  is  cast  in  brass,  and  is  worked  by  a  single 
eccentric  and  varying  link.     In  some  examples  the  valve  is  circular; 


Fig.  277.— Link; 
K,  Link.     B,  Su.spending  pin.     cc.  Eyes  for 
eccentric  rods.    D,  Block  on  slide-valve  rod. 


Fig.  278. — Gridiron  Expansion  Valves. 
A,  Expansion  valve,     b,  Facing  for  do.     c.  Steam  pipe,     d,  Main  slide  valve,     e,  Cylinder. 

by  adopting  this  shape  the  steam  pressure  is  taken  off  the  back, 
and  the  valve  is  consequently  more  easily  handled. 


MARINE   ENGINES. 


395 


Fig.  279. — Throttle  Valve. 
A,  Throttle  valve,     b,  Spindle  for  do.     c,  Chest. 


The  throttle  valve  is  generally  of  the  butterfly  type,  and  is  located 
between  the  expansion  valve  and  the  boiler,  having  hand  gear  for 
each  valve  passing  along  to  the  starting  platform.  Some  engineers 
use  only  one  handle  for  both  valves,  but  this  arrangement  is  not 
advisable,  as  one  engine  or  cylinder  may  require  more  or  less 
throttling  than  the  other,  although  the  cylinders  are  lying  quite 

close  together.     A 

■S^ ^^SS  ^^^^  ^^*  11        1  ii 

^  ^^^  ^  ^  small  plug  or  other 

valve  is  fitted  be- 
tween the  gridiron 
expansion  casing 
and  the  main  valve 
casing,  by  which 
steam  can  be  admitted  from  the  one  to  the  other,  in  the  event  of 
the  engines  stopping  at  a  part  of  the  stroke  where  the  expansion 
valve  covers  the  ports,  and  it  would  be  difficult  to  start  again 
without  this  auxiliary  valve. 

The  blow-throitgh  valve  is  a  common  spindle  one,  guided  at  the 
bottom  through  a  hole  in  the  centre  boss  cast  along  with  the  seating, 

with  a  single  feather;  or  the  valve  may 
be  of  the  three-feather  type,  turned  to 
the  inside  diameter  of  the  seating.  The 
former  has  a  long  spindle  at  the  top, 
which  passes  through  a  stuffing  box  on 
the  cover  of  the  valve  box.  This  spindle 
is  fitted  with  a  slot  crosshead  for  the 
lifting  arm  to  pass  through,  with  a  lever 
and  rod  passing  along  to  the  starting 
platform.  Some  makers  have  used  a 
small  slide  valve,  with  steam  and  ex- 
Fig.  aSc-Biow-through  Vaive.      haust   ports  placed  on  the  top  of  the 

A,Valve  and  spindle.    B  Chest,    c,  stuffing         jj^jg  ^j^j^       ^^^^^       pSSSagCS       and 

box  and  gland,     d.  Lifting  lever.  -'  '  r^  & 

valve  chest  cast  in  brass.  This  valve 
is  worked  by  hand  off  the  platform,  and  can  be  used  for  blowing 
through,  or  even  turning  the  engines  gently,  in  which  respect 
it  serves  as  a  means  of  starting  the  machinery  independently 
of  the  main  slide  valve — a  great  desideratum  in  large- powered 
engines.  Plain  plug  valves  may  be  conveniently  used  for  the  blow 
through,  but  it  is  not  advisable  to  adopt  them  for  heavy  engines. 
The  plug  should  be  packed  with  hemp  at  the  top,  having  a  suitable 


39^ 


MODERN   STEAM   PRACTICE. 


packing  gland,  and  the  bottom  or  small  end  of  the  plug  is  merely 
fitted,  and  ground  into  the  seating,  which  is  cast  solid  at  the  end ; 
by  this  means  no  leakage  can  occur  except  at  the  top,  which  is 
made  steam-tight  by  the  packing  gland. 

The  escape  or  relief  valve,  fitted  to  the  bottom  of  the  cylinder 
cover  and  to  the  front  end  of  the  cylinder,  is  intended  to  allow  the 
escape  of  the  water  which  finds  its  way  into  the  cylinder  from 
priming  and  condensation  of  the  steam.  It  consists  of  a  disc  valve 
with  a  spring  fitted  to  the  top,  screwed  down  sufficiently  tight  to 
resist  the  steam  pressure  acting  on  the  internal  area  of  the  valve. 
The  valve  can  only  be  opened,  and  the  water  which  is  not  com- 
pressible ejected,  by  the  piston  striking  against  the  water,  and 
forcibly  lifting  the  valve,  compressing  the  spring,  which  again 
reacts  when  the  cylinder  is  free  of  water.  The  valve  should  be 
inclosed  in  a  light  dome,  with  a  hole  at  the  bottom  side  for  allowing 
the  hot  water  to  escape  downwards 
into  the  bilges.  In  other  examples  a 
dash  or  splash  plate  is  cast  along  with 
the  valves,  when  placed  horizontally 
and  vertically;  the  plate  being  of  a 
curved  shape,  the  water  escaping  all 
round  the  valve  is  returned  or  thrown 
back  again,  and  so  prevented  from  being 
scattered  about  the  engine  room,  and 
scalding  the  engineers  or  those  in  at- 
tendance. The  spring  is  usually  screwed 
down  with  a  crosshead,  through  which 
the  valve  spindle  passes  loosely  through  a  hole  bored  in  the  centre. 
At  each  end  of  the  crosshead  is  a  column,  secured  to  the  valve  seat  at 
one  end,  and  the  other  end  screwed,  passing  through  a  hole  in  the 
crosshead,  and  fitted  with  nuts  above  and  below.  The  spring  is  placed 
around  the  spindle,  between  the  valve  and  the  crosshead,  which  by 
means  of  the  nuts  is  screwed  up  carefully,  compressing  the  valve  to 
a  little  above  the  working  pressure  of  the  steam  in  the  cylinders, 
which  can  be  easily  adjusted  when  the  engines  are  started,  and  then 
the  nuts  below  the  crosshead  can  be  screwed  hard  up ;  in  this  way  the 
valve  is  guided  at  the  top  through  the  crosshead,  and  at  the  bottom 
the  spindle  passes  through  the  hole  in  the  central  boss  cast  along 
with  the  valve  seating.  Some  engineers  dispense  with  the  movable 
crosshead,  using  merely  a  bow  or  fixed  crosshead  of  wrought  iron 


Fig.  281. — Relief  Valve  with  movable 

Crosshead. 

A.  Valve  and  spindle.     B,  Valve  seat. 

c,  Spring.     D,  Crosshead.     E  E,  Columns. 

F,  Baffle  piece. 


MARINE  ENGINES. 


397 


secured  to  the  seating  with  nuts,  and  a  central  boss  at  the  top,  for 
the  reception  of  a  screwed  stud  for  tightening  up  or  compressing 
the  spring;  one  cap  being  cast  along  with  the  valve  for  the  spring  to 
rest  on,  and  another  cap  at  the  top  of  the  spring  on  which  the  screw 


r^ 

)      < 

E 

if^ 

Jt-k   -D 

rn^wm 

Fig.  283.— Relief  Valve  with  Stud  on  Cylinder  Cover. 

A,  Valve.     B,  Valve  seat,     c,  Spring.     D,  Cap. 
E,  Set  screw.     F,  Stud.     G,  Baffle  piece.     H,  Cylinder  cover. 


Fig.  284. — Relief  Valve  with  Dome. 

A,  Valve  and  spindle.     B,  Valve  seat. 
C,  Spring.     D,  Baffle  dome. 


for  compressing  the  spring  bears:  in  this  arrangement  the  valve 
is  guided  by  the  spindle  passing  through  the  seating.  A  very 
simple  form  of  this  description  dispenses  with  the  wrought-iron 
bow,  a  stud  being  screwed  into  the  cylinder  cover  and  end,  through 
which  the  screw  for  tightening  up  the  spring  passes ;  while  in  other 
forms  the  dome  fitted  over  the  spring  for  protecting  it  from  being 
injured,  as  well  as  for  preventing  the  water  flying  about  the  engine 
room,  is  fitted  with  a  boss  at  the  top,  through  which  the  tightening- 
up  screw  passes,  the  dome  being  bolted  to  the  covers  and  end  with 
stud  bolts.     Many  prefer  a  fixed  pressure  on  the  relief  valve,  but. 


398  MODERN    STEAM   PRACTICE. 

on  the  whole,  we  think  it  should  be  fitted  with  set  screws,  to  adjust 
the  pressure  against  the  valve  at  any  time  to  suit  the  reduction  in 
steam  pressure  that  may  be  considered  advisable  after  the  boiler 
has  worked  for  a  lengthened  period.  Some  makers  have  fitted  an 
additional  valve  opening  downwards,  seated  on  the  main  relief 
valve,  and  opened  by  hand,  while  another  valve  of  india  rubber  is 
placed  on  the  top  of  the  main  relief  one,  so  that  when  the  additional 
valve  is  opened,  in  the  event  of  violent  priming  at  the  return  stroke 
of  the  piston,  the  disc  of  india  rubber,  or  metal  valve  if  so  fitted, 
closes,  and  does  not  impair  the  vacuum.  This  is  a  complicated 
arrangement,  not  in  general  use;  and  the  same  object  is  attained 
by  fitting  a  plug  valve  at  the  bottom  of  each  end  of  the  cylin- 
der, worked  simultaneously  from  the  starting  platform,  and  which 
can  be  opened  when  violent  priming  occurs,  or  in  the  act  of 
blowing  through  before  starting  the  engine, — in  the  same  way  as 
the  plug  valves  in  the  locomotive  engine  cylinder,  which  are  left 
open  for  a  considerable  time  to  blow  out  thoroughly  all  the  water 
from  the  cylinders.  Some  first-class  engineers  consider  that  greater 
safety  would  be  insured  by  dispensing  with  the  springs  for  holding 
down  the  relief  valves,  and  this  seems  a  step  in  the  right  direction ; 
for  when  valves  are  so  arranged  that  they  are  held  down  simply 
by  the  steam,  and  have  the  means  of  blowing  all  the  water  back 
again  into  the  steam  pipes,  and  collecting  it  in  a  suitable  separator, 
we  secure  two  advantages,  namely,  that  the  valves  are  not  so  liable 
to  stick  or  get  damaged,  and  that  the  hot  water  does  not  fly  about, 
but  is  received  into  the  separator,  which  can  be  run  off  occasionally. 
For  this  purpose,  double-beat  valves,  giving  a  large  circumferential 
area  for  the  water  to  escape,  or  common  spindle  valves,  are  fitted  to 
the  top  of  the  cylinder,  in  valve  chests,  which  communicate  by 
pipes  with  the  cylinder  on  the  bottom  of  the  valve  and  the  steam 
pipe  on  the  top  of  the  valve;  the  steam  pressure  above  the  valve 
being  greater  than  that  in  the  cylinder,  the  valves  are  of  course 
held  down  by  the  difference  of  pressure,  and  the  water  is  ejected 
as  in  ordinary  arrangements,  with  this  difference  that  it  is  collected 
in  a  vessel  for  the  purpose,  instead  of  finding  its  way  into  the 
bilges. 

Liibricators. — Grease  cups  are  fitted  to  the  steam  ports  at  the 
front  and  back  of  the  cylinder,  for  lubricating  the  valve  and  piston, 
the  lubricant  being  drawn  in  with  the  vacuum.  These  cups  should 
be  fitted  in  connection  with  a  plug  valve  having  a  screwed  part  at 


MARINE   ENGINES.  399 

the  top,  to  suit  the  screw  of  the  indicator,  with  a  pipe  connected 
between  the  plug  valves,  so  that  an  indicated  card  may  be  taken 
from  the  front  end  and  back  of  the  cylinder  without  shifting  the 
instrument.  The  pipe  between  the  plug  valves  should  be  fitted 
with  an  additional  valve,  for  cutting  off  the  communication  when  it 
is  desirable  to  take  a  card  from  the  front  end,  and  vice  versa.  The 
liquid  tallow  is  poured  into  the  cup,  and  flows  through  a  hole  into 
the  hollow  plug;  the  valve  is  then  turned  by  hand,  bringing  the 
hole  into  communication  with  a  small  hole  on  the  opposite  side 
leading  into  the  port,  and  the  oil  is  drawn  into  the  cylinder  by  the 
vacuum.  Sometimes  a  plug  tap  is  fitted  into  the  tallow  cup,  and 
opened  and  shut  by  hand ;  but  this  operation  requires  some  care,  as 
it  is  evident  that  it  must  not  be  opened  until  the  vacuum  is  formed, 
or  the  tallow  would  be  blown  out  of  the  cup.  The  attendant  must 
therefore  watch  the  motion  of  the  engine,  and  shut  off  the  com- 
munication with  the  cylinder  before  the  steam  is  again  admitted, 
so  as  to  allow  the  tallow  to  be  drawn  into  the  cylinder  with  the 
vacuum — an  operation  requiring  some  dexterity,  with  the  piston 
doing  sixty  strokes  or  so  per  minute.  It  is  therefore  preferable  to 
use  the  hollow  plug  valve,  as  described  above. 

We  now  come  to  consider  the  piston  for  the  various  forms  of 
horizontal  marine  engines.  In  the  construction  of  this  part  the 
main  point  to  be  studied  is  to  provide  ample  surface  for  wear. 
The  thrust  is  imparted  more  directly  on  the  piston  in  the  single- 
trunk  type  than  where  there  is  a  trunk  at  each  end  of  the  cylinder. 
In  the  latter  arrangement  the  trunks  form  a  hollow  support  for  the 
piston,  while  the  thrust  of  the  connecting  rod  is  taken  on  the  bushe.s 
and  packing  glands  in  the  ends  of  the  cylinder,  and  the  rubbing 
surface  of  the  piston  can  be  made  much  less  than  for  any  other 
class  of  horizontal  engine.  While  other  pistons  must  have  a  broad 
surface  for  wear,  the  packing  rings  for  the  double-trunk  system 
have  in  some  instances  merely  slight  steel  or  brass  hoops  for  making 
them  steam-tight.  Pistons  for  two  or  more  piston  rods  on  the 
return  connecting-rod  principle  require  less  area  for  the  rubbing 
surface  than  those  for  direct-action  single  piston-rod  engines,  the 
former  being  partly  balanced  by  the  long  rods  and  heavy  cross- 
heads,  the  stuffing  boxes  serving  as  a  fulcrum  by  which  the  weight 
of  the  piston  is  partly  taken  off  the  cylinder  surface,  and  this  tends 
to  prevent  them  wearing  so  rapidly  as  in  the  direct-acting  type, 
although  the  diameter  of  the  piston  rod  in  the  latter  is  increased  to 


400 


MODERN   STEAM   PRACTICE. 


Fig.  285. — Piston  Rings. 

A  A,  Pistons.     B  B,  Packing  rings,     cc,  Junk  rings. 

D  D,  Bolts  with  recessed  nuts.     E,  Bolt  with  hole  tapped 

in  the  body  of  the  piston. 


gain  more  surface  in  the  glands,  and  by  the  increased  weight  of 
the  rod  and  its  adjuncts  to  reheve  the  piston  rubbing  surface.  The 
total  rubbing  surface  or  depth 

m 


of  the  piston,  for  double  trunks, 
may  be  taken  at  one-eleventh 
of  the  diameter  of  the  cylinder ; 
for  double  piston-rod  engines 
on  the  return  connecting  prin- 
ciple, one -sixth;  for  single 
piston-rod  and  single-trunk 
arrangements,  one-fifth:  this 
depth  being  the  breadth  over 
the  surface  in  contact  with  the 
cylinder.  Most  pistons  have 
projecting  rings  cast  along 
with  the  junk  ring,  and  some 

have  also  projecting  rings  cast  along  with  the  main  body  of  the 
piston — both  having  in  view  the  equalization  of  the  junk  ring  and 
end  surface  in  connec-  h 

tion  with  the  main 
packing  ring;  this  is 
necessary,  as  the  rub- 
bing surfaces  on  the 
junk  and  back  ring  have 
the  weight  of  the  piston, 
and  in  some  instances 
the  thrust  of  the  con- 
necting rod,  to  sustain, 
while  the  packing  ring 
has  not  so  much  duty 
to  perform.  In  order 
to  make  the  junk  ring 
and  other  surfaces  to 
bear  more  equally,  and 
to  keep  the  piston  cen- 
tral with  the  cylinder, 
two  pieces  of  cast  iron 
are  placed  on  the  under 
side,  between  the  packing  ring  and  the  main  body  of  the  piston, 
pitched  about  one-fifth  of  the  diameter  of  the  piston  apart;  in  this 


Fig.  286.— Piston. 

A,  Piston.  B,  Packing  ring,  c  c  c,  Springs,  dd,  Cast-iron  pieces. 
E  E,  Bosses  for  piston  rods.  F,  Boss  for  air-pump  rod.  G  G,  Ribs 
to  strengthen  the  body  of  the  piston,      h.  Tongue  at  division. 


MARINE   ENGINES. 


401 


Way  the  weight  of  the  piston  is  transmitted  through  rigid  blocks  to 
the  packing  ring,  which  bears  on  the  internal  surface  of  the  cylinder. 
Short  springs  of  a  bow  shape  are  placed  all  round  the  packing  ring, 
to  keep  it  well  up  to  the  cylinder  surface.  In  some  cases  these 
springs  are  of  a  U  shape,  let  into  recesses  in  the  body  of  the  piston. 
The  main  body  of  the  piston  is  strengthened  with  ribs  radiating 
from  the  centre,  and  has  the  necessary  bosses,  which  are  bored  out 
for  the  reception  of  the  piston  and  air-pump  rods;  the  holes  are 
sometimes  tapered  to  receive  the  ends  of  the  rods,  and  in  other 
examples  they  are  quite  parallel ;  in  the  former  case,  the  piston  rod 
is  screwed  tightly  against  the  cone,  and  in  the  latter  against  a 
shoulder  left  on  the  rod  itself  Holes  are  cast  in  the  body  of  the 
piston  for  the  purpose  of  extracting  the  cores ;  these  are  accurately 

bored  out  with  a  slight  cone,  and 
plugged  up  with  cast-iron  plugs, 
having  a  thin  coating  of  red  lead 
to  make  the  joint  perfectly  steam- 
tight.  They  are  further  secured 
by  boring  holes  on  the  circum- 
ferential line  of  the  joint,  which 
are  tapped  for  the  reception  of 
brass  or  wrought- iron  screws, 
firmly  screwed  in.  One-half  of  the 
screw  being  in  the  body  of  the 
piston  and  the  other  half  in  the 
plug;  these  screws  are  cut  off  flush  with  the  surface  of  the  casting. 
The  junk  ring  is  held  down  by  bolts  screwed  into  the  cast-iron 
piston,  or  brass  or  wrought -iron  nuts  are  fitted,  recessed  into  it, 
having  a  thickness  of  metal  all  round;  the  bolts  are  kept  from 
turning  by  a  screwed  stud  recessed  in  the  head,  and  tapped  into 
the  junk  ring.  The  ring  is  accurately  turned,  as  also  the  surfaces 
bearing  on  the  piston  and  the  spring  ring,  which  are  then  scraped 
to  a  true  surface,  and  made  perfectly  steam-tight  After  the  pack- 
ing ring  is  turned,  an  oblong  hole  is  cut  out  at  the  centre  at  that 
part  where  the  ring  is  cut  through,  and  a  brass  piece  with  a  flange 
all  round  is  fitted  into  the  hole,  filling  it  up,  while  the  flanges  make 
the  spring  joint  steam-tight;  the  end  of  the  brass  filling-in  piece 
is  secured  to  the  packing  ring  at  one  end  with  screwed  studs,  and 
a  wrought-iron  bridle  is  placed  over  the  tongue,  and  secured  like- 
wise at  one  end  to  the  packing  ring.    The  object  of  this  arrangement 

26 


Fig.  287. — Block  Piece  for  Piston  Ring. 
A,  Piston.      B,  Junk  ring.       c,  Packing  ring. 
D,  Tongue.     E,  Bridle. 


402  MODERN    STEAM    PRACTICE. 

is  to  compress  the  packing  ring-,  by  the  insertion  of  a  wedge  between 
the  tongue  piece  at  the  fast  end  and  the  bridle  at  the  loose  end,  so 
that  when  the  wedge  is  driven  in  between  the  two  the  packing  ring 
is  drawn  together,  and  can  be  readily  placed  in  the  piston  when  in 
the  cylinder ;  the  cotter  is  then  drawn  out,  and  the  packing  ring 
expands  to  its  original  size,  and  fills  the  cylinder  somewhat  tightly. 
The  projections  left  on  the  junk  rings  and  the  body  of  the  piston 
must  have  recessed  parts  in  the  cover  and  end  of  the  cylinder,  with 
sufificient  clearance  at  the  end  and  round  the  projections;  and  it  is 
advisable  to  leave  recessed  parts  at  both  ends  of  the  cylinder, 
making  the  part  bored  out  somewhat  shorter  than  the  actual  stroke 
of  the  piston,  so  that  the  rubbing  surface  travels  over  it  at  each  end, 
and  prevents  a  groove  forming  in  the  cylinder  that  would  eventu- 
ally prove  destructive  to  the  engine,  in  the  event  of  the  connecting 
rods  requiring  lining  up  in  the  brasses,  by  causing  the  piston  to 
strike  hard  against  the  projections.  Sometimes  the  piston  for 
direct-acting  single  piston-rod  engines  is  dished  out  or  formed  of  a 
curved  shape,  with  the  view  of  getting  more  room  for  the  crosshead, 
the  gland  for  the  rod  being  recessed  into  the  end  of  the  cylinder. 
This  is  the  only  advantage  to  be  derived  from  this  plan,  and  it  is 
but  rarely  adopted.  The  fittings  of  such  pistons  are  identical  with 
those  for  the  plain-ended  arrangement.  When  annular  cylinders 
are  adopted  for  high  and  low  pressure  combined  engines,  the  small 
piston  for  the  high-pressure  cylinder  is  similar  to  an  ordinary  one, 
but  the  piston  for  the  annular  cylinder  must  have  two  packing 
rings,  the  outside  ring  bearing  on  the  cylinder  surface,  as  in  ordinary 
arrangements,  but  the  internal  packing  ring  bears  on  the  inside 
diameter  of  the  ring,  the  ring  being  pressed  up  against  the  barrel 
of  the  high -pressure  cylinder  with  strong  steel  springs.  These 
pistons  are  generally  connected  to  the  crosshead  by  a  central  piston 
rod  for  the  high-pressure  cylinder,  and  two  side  ones  for  the  low- 
pressure  cylinder,  with  one  crosshead  common  to  both.  There 
must  be  block  pieces  fitted  between  each  packing  ring  and  the 
body  of  the  pistons,  to  keep  them  all  fair  with  one  another.  The 
packing  rings  of  all  pistons  are  generally  made  thicker  at  the  bottom 
where  these  blocks  are  fitted,  and  thinner  at  the  top  where  the 
ring  is  cut;  this  is  necessary,  as  in  all  horizontal  arrangements  the 
severest  strains  and  wear  are  undoubtedly  at  the  bottom  of  the 
piston. 

As  bearing  on  this  subject  the  following  extracts  are  from  a 


MARINE   ENGINES.  4O3 

paper  on  '*  Pistons,"  read  by  Mr.  James  Howden  before  the  Institu- 
tion of  Engineers  and  Shipbuilders  in  Scotland,  session  1880- 
81: — "Absolute  steam-tightness  in  a  piston  at  work  very  seldom 
occurs.  It  is  much  more  difficult  to  secure  than  is  generally  sup- 
posed. Probably  steam-tightness  has  never  existed  in  any  piston 
with  a  single  packing  ring  after  it  has  worked  a  short  time,  even 
though  the  piston  has  been  perfectly  steam-tight  at  first  starting. 
On  removing  the  junk  ring  of  any  such  piston  after  it  has  worked 
for  some  time,  evidences  of  steam  having  passed  between  the  faces 
of  the  packing  ring  and  junk  ring  or  piston  flange  into  the  interior 
space  are  quite  apparent.  The  scraped  or  ground  faces  are  in 
places  dull  and  steam  worn,  and  if  oil  or  grease  has  been  used  to 
lubricate  the  cylinder,  grease  and  dirt  will  be  found  in  the  space 
inside  of  the  packing  ring. 

"  In  pistons  with  double  packing  rings  leakage  over  their  end 
faces  is  sought  to  be  overcome  by  a  pressure  endwise  from  a  spring 
which  presses  the  packing  rings  at  same  time  outwards  towards  the 
walls  of  the  cylinder.  This  causes  undue  friction  and  wear  of  the 
cylinder  and  packing  rings;  and  where  there  is  much  wear  there 
will  soon  necessarily  be  leakage  through  the  packing  rings  and 
interior  of  the  piston.  The  dirt  and  grease  often  so  plentifully 
found  inside  the  packing  rings,  show  that  steam  has  been  passing 
about  as  freely  to  the  inside  of  the  piston  as  into  the  cylinder  itself 

"The  element  of  friction  is  an  important  one,  and  a  piston  at 
once  steam-tight  and  practically  frictionless  possesses  a  value  which 
it  would  be  difficult  to  overestimate.  There  cannot,  of  course,  be 
an  entire  absence  of  friction,  but  it  may  be  reduced  to  the  least 
possible  extent.  The  piston  of  a  well-made  indicator  is  an  example 
of  a  piston  steam-tight  under  any  usual  pressure,  and  practically 
frictionless.  It  works  Avithout  any  pressure  outwards  against  the 
walls  of  the  cylinder.  In  pistons  with  packing  rings  and  compen- 
sating springs,  one  of  their  greatest  defects  is  the  universal  excess 
of  pressure  outwards  against  the  cylinder.  It  is  generally  supposed 
that  when  a  cylinder  is  found  smooth  and  polished,  that  the  piston 
is  working  with  very  little  friction.  This  is  often  a  delusive  infer- 
ence, for  in  a  well-lubricated  cylinder  the  packing  rings,  if  bearing 
fairly  all  round,  will  make  a  smooth  skin  on  the  cylinder,  even 
under  a  strong  pressure  against  it." 

The  author,  in  describing  a  new  form  of  piston,  the  invention  of 
Mr.   Wm.   Rowan  of  Belfast,  states: — "This   piston    is,   however, 


404 


MODERN   STEAM   PRACTICK 


distinguished  from  all  other  pistons  of  this  class  by  effecting  the 
endwise  and  outward  pressures  by  separate  springs,  each  exactly 
suited  for  the  work  they  have  to  perform.  As  I  have  shown,  the 
pressure  of  the  packing  rings  endwise  should  be  strong,  and  their 
pressure  outward  against  the  cylinder  light,  or  exactly  the  reverse 
of  what  occurs  in  all  other  double  packing  ring  pistons. 

"  The  springs  are  extremely  simple  in  their  character  and  con- 
struction. They  are  made  from  light  hoop  spring  steel,  varying  in 
breadth  and  thickness  to  suit  the  diameter  of  the  piston.  Breadths 
from  Yz  inch  to  2  inches,  and  thicknesses  from  yV  inch  to  -^  inch, 
will  serve  for  pistons  from  I  to  6  feet  in  diameter.  To  one 
seeing  them  for  the  first  time  these  springs  look  quite  inadequate  to 
accomplish  the  ends  proposed.     It  is  surprising  to  see  a  spring  of 


A 

B 

y 

^ 

^5^^^ 

^""''^'^''^''"^ 

1 

Figs.  287A,  287B.— A,  Junk  ring.     B  B,  Packing  rings,     c,  Spring.     D,  Flange  on  piston. 
E,  Part  where  the  packing  rings  are  cut, 

a  few  pounds  weight  in  a  large  piston  accomplishing  an  effect 
to  obtain  which  in  other  pistons  continuous  springs  weighing  several 
hundredweights  are  used. 

"The  spring  for  pressing  the  packing  rings  against  the  junk  ring 
and  piston  flange  is  bent  round  on  its  flat  to  the  required  diameter, 
and  may  have  projections  on  either  side  alternately  at  definite 
distances  apart,  or  the  projections  may  be  similarly  placed  on  the 
contiguous  faces  of  the  packing  rings,  between  which  these  springs 
are  placed.  The  preferable  mode,  however,  and  that  usually 
adopted,  is  to  have  the  projections  on  the  spring  itself  in  the  form 
of  waves,  as  shown  in  Figs.  287A  and  287E,  and  where  they  are 
shown  in  position  between  the  two  packing  rings.  It  is  found  that 
springs  made  in  this  manner  to  definite  proportions  of  height  and 
length  of  waves,  now  fully  ascertained  for  all  dimensions,  can  be 
made  to  give  an  almost  unlimited  pressure  when  screwed  to  re- 
quired position,  and  the  elasticity  remains  good  for  years. 


MARINE  ENGINES. 


405 


"  The  springs  for  pressing  the  packing  rings  outwards,  against  the 
cylinder,  are  made  simply  of  the  steel  hoop  bent  round  to  somewhat 
more  than  the  circle  of  the  inside  of  the  packing  rings.  The  ends 
meet  inside  the  thin  flat  sleeve  piece  shown  in  Figs.  287c — 287E." 

A  screwed  part  at  the  end  of  the  piston  rod,  of  less  diameter 


4o6 


MODERN    STEAM    PRACTICE. 


than  the  main  part  of  the  rod,  receives  a  large  nut,  by  which  the 
piston  rod  is  secured  to  the  piston.  The  part  of  the  rod  passing- 
through  the  piston  is  of  increased  diameter  and  cone-shaped,  this 
cone  is  drawn  through  a  corresponding  hole  bored  in  the  piston, 
and  held  firmly  by  the  large  nut  at  the  end,  which  is  kept  from 
turning  backwards  by  a  split  pin  bearing  on  it,  and  passing  through 
a  hole  bored  in  the  end  of  the  rod.  This  cone  in  some  examples 
is  no  larger  than  the  rod  at  the  one  end,  and  is  reduced  at  the  end 
nearest  the  nut,  in  which  case  no  raised  part  is  required  to  be  forged 
on  the  rod ;  a  collar,  however,  is  sometimes  left  to  screw  the  piston 
against.     Some  makers  prefer  having  that  part  of  the  rod  which 


Fig.  288.— Tapered  Rod  and  Nut  for  Piston. 

A,  Piston.     B,  Taper  on  rod.     C,  Nut. 
D,  Split  pin. 


Fig.  289. — Parallel  Rod  and  Nut  for  Piston. 

A,  Piston.    B,  Parallel  part  on  the  piston  rod.    c.  Nut. 
D,  Split  pin. 


passes  through  the  piston  quite  parallel,  or  nearly  so,  with  a  shoulder 
formed  by  the  reduction  of  diameter,  against  which  the  piston  is 
screwed.  The  screw  is  generally  of  a  V  form,  rounded  at  the  top 
and  bottom  of  the  thread ;  others  are  cut  square,  but  the  V  thread 
is  preferable.  The  nut  in  most  examples  projects  from  the  body 
of  the  piston,  and  bears  on  a  turned  raised  part  formed  on  the 
casting;  in  others  it  is  recessed  into  the  piston,  and  in  others  again 
it  is  flush  with  it,  or  a  small  projection  of  the  nut  is  left,  so  that  it 
can  be  turned  round  with  an  ordinary  spanner.  When  the  rod 
passes  through  a  crosshead,  its  end  is  turned  down  quite  parallel 
and  secured  to  the  crosshead  with  a  nut,  in  the  same  way  as  for  the 
piston.  Some  engineers  place  a  jam  nut  on  the  back  of  the  main 
one,  with  split  pins  passing  through  both  nuts,  thus  making  a  very 
secure  fastening.  These  lock  nuts  should  be  placed  on  all  the 
parts  which  are  liable  to  shake  loose,  more  especially  for  direct- 
action  engines,  as  the  speed  at  which  these  are  driven  is  liable  to 


MARINE   ENGINES. 


407 


loosen  the  parts  if  not  ^properly  secured.  For  direct-acting  single 
piston-rod  arrangements  a  T-shaped  piece  is  formed  on  the  end  for 
taking  the  crosshead,  or  brasses,  which  are  secured  to  the  rod  by- 
two  bolts  passing  through  the  T  piece,  brasses,  and  cap;  the  nuts 
being  secured  at  the  ends  of  the  bolts  with  split  pins.  The  nut 
can  be  fitted  with  a  washer  with  pin  let  into  the  cap,  and  a  small 
set  screw  placed  at  the  top  of  the  one  and  the  bottom  side  of  the 
other,  passing  through  the  washer  and  bearing  in  a  hollow  turned 
in  the  reduced  part  of  the  nut.  With  the  T  form  there  must  not 
be  any  raised  part  on  the  piston  rod  at  the  piston  end,  so  as 
to  allow  the  glands  and 
bushes  to  pass  freely 
along ;  these  must  of 
course  be  placed  on  the 
rod  before  it  is  secured  to 
the  piston,  for  it  is  not 
advisable,  under  any  cir- 
cumstances, to  cut  the 
glands  in  two,  as  some 
prefer  doing  in  oscillat- 
ing arrangements. 

The  guides  and  a^oss- 
head  for  double  piston- 
rod  engines,  on  the  return 
connecting-rod  principle, 
are  best  arranged  with 
two  guides  or  motion 
bars,  one  on  each  side  of 
the  connecting  rod.  By 
this  arrangement  the 
crosshead  is  well  sup- 
ported at  the  ends,  and 
the  strain  on  the  guide  bars  is  in  a  direct  line  with  the  centre  line  of 
the  cylinder.  The  crosshead  is  a  circular  forging,  with  arms  forged 
on  for  taking  the  piston  rods.  In  some  cases  it  is  turned  quite 
parallel  between  the  arms,  these  being  forged  on  at  right  angles  to 
the  main  part  of  the  crosshead ;  in  others  a  collar  is  formed  on  each 
side  between  the  connecting-rod  brasses  and  the  guide  blocks. 
When  the  arms  are  forged  on  at  an  angle  with  the  crosshead,  it  is 
advisable  to  make  the  connecting-rod  bearing  of  a  larger  diameter, 


Fig.  290. — Crosshead  Gudgeon  and  Motion  Bars. 
A,  Gudgeon.        B  B,  Slide  blocks.        cc.  Motion  bars. 


408  MODERN   STEAM   PRACTICE. 

finishing  up  the  arms  quite  square,  and  fitting  the  sliding  blocks  of 
brass  to  them.  When  this  part  of  the  crosshead  is  turned,  the 
sliding  blocks  are  bored  out,  and  are  held  in  position  with  a  side 
flange;  the  blocks  are  planed  at  the  top  and  bottom.  In  some 
instances  cast-iron  blocks  have  been  used,  lined  on  the  rubbing 
surfaces  with  white  metal.  The  motion  bars  are  of  cast  iron,  the 
bottom  one  is  cast  along  with  the  condenser,  and  the  top  one,  of  an 
I  section,  is  bolted  down  at  each  end  with  one  large  bolt,  passing 
down  through  the  vertical  distance  pieces  cast  along  with  the  bar; 
or  two  smaller  bolts  passing  through  flanges  at  the  bottom  may  be 
conveniently  adopted,  in  which  case  the  bottom  motion  bar  is 
generally  raised  up  from  the  condenser  casting,  having  strength- 
ening ribs  cast  along  with  it.  One  or  more  oil  cups,  provided 
with  covers  and  wick  siphon  pipes,  should  be  cast  on  the  top  of 
the  guide  bar,  to  lubricate  the  sliding  surfaces.  The  crosshead  in 
other  arrangements  is  let  into  the  pillow-block  pieces  (fitted  with 
caps  and  bolts),  which  are  cast  along  with  a  T  piece  at  the  bottom, 
placed  centrally,  and  which  is  fitted  with  a  separate  brass  casting, 
having  clips  at  the  end  to  take  the  sliding  strain.  This  guide  block 
has  a  large  flat  surface  at  the  bottom,  but  the  surface  at  the  top  is 
not  of  so  large  an  area,  owing  to  the  thrust  of  the  connecting  rod 
being  neutralized  by  the  weight  of  the  crosshead  and  adjuncts. 
'Some  engineers,  indeed,  have  left  a  small  space  between  the  top 
surfaces,  thus  showing  clearly  that  the  top  thrust  is  but  little  felt. 
The  guide  bar  is  of  a  trough  section,  and  is  bolted  down  to  the 
condenser  casting,  having  means  of  adjusting  it  to  suit  the  wear  of 
the  brass  sliding  piece.  The  lubrication  of  the  parts  is  effected  by 
means  of  an  open  oil  well  at  each  end,  which  is  kept  constantly  full; 
the  bottom  sliding  piece  travels  a  somewhat  greater  length  than 
the  surface  provided  on  the  trough  guide  plate,  consequently  its 
bottom  skims  the  oil  in  the  receivers  at  each  end,  thus  keeping  the 
guide  plate  thoroughly  lubricated.  All  these  arrangements  of 
crossheads  are  suited  for  plain  connecting  rods;  some  builders, 
however,  adopt  forked  connecting  rods,  having  the  crosshead,  or 
rather  the  pin  for  the  connecting  rod,  fixed  firmly  on  the  rod, 
working  in  a  single  pillow  block  and  guide  piece,  provided  with 
caps  and  brasses,  as  in  the  previous  example.  The  crosshead  for 
taking  the  piston  rods  can  by  this  means  be  forged  and  finished 
quite  flat,  and  it  is  bolted  to  the  guide  block  with  the  two  large  bolts 
taking  the  cap  and  securing  the  brasses  for  the  connecting-rod  pin. 


MARINE   ENGINES. 


409 


This  arrangement  of  crosshead  is  certainly  preferable  to  those  having 
the  arms  forged  on  at  an  angle  from  the  connecting  rod  bearing,  as 
it  assumes  a  more  direct  form  of 
beam,  loaded  at  the  end  with  the 
steam  pressure  communicated  from 
the  piston  through  the  piston  rods, 
taken  centrally  with  the  connecting 
rod,  which  in  its  turn  acts  on  the  arms 
of  the  cranked  shaft,  the  bearing  of 
which  is  subjected  to  torsional  stress. 
We  have  now  to  consider  the  con- 
nection between  the  piston  rod  and 

the  connecting  rod   for  direct-action  ^_____ 

single  piston-rod  arrangements.    The  j        '"^3z^,,.lZl^ 

Ur.....   f.r  t.l.;no-   fhP    forked   end  of  fe^^^^^^^^^ 


brasses  for  taking  the  forked  end  of 
the  connecting  rod   are  cast   in  two 

halves,  on  each  of  which  is  cast  a  ^^^^^  c  c,  BoUs  and  nuts,  d,  Crosshead. 
bottom  guide  piece;  they  are  grooved      ee,    Eyes    for   the   piston    rods.       f,  Brass 

sliding  piece. 

out  for  the  reception  of  a  wedge  plate, 

the  bottom  of  which  is  parallel  with  the  centre  line  of  the  rod,  but  of 
a  wedge  shape  on  its  upper  surface,  which  bears  on  the  brass  pieces, 
and  which  is  secured  at  one  end,  but  having  the  means  of  adjusting 


Fig.  291. — Crosshead  for  Piston  Rods. 
A,  Pillow  block  on  crosshead  fitted  with  brasses. 


Fig.  292. — Crosshead  for  Single  Piston  Rod. 

A,  Brass  crosshead.     B,  Cap.     c,  T  piece  forged  on  the  piston  rod.     D  D,  Bolts  and  nuts, 
E,  Adjustable  plate,     f.  Guide  for  crosshead. 

the  sliding  brass  against  the  bottom  guide  plate,  as  in  the  examples 
already  described.  The  piston  rod  has  a  T  piece  for  attachment 
to  these  brasses,  and  at  the  connecting-rod  end  a  cap  is  fitted;  these 
are  all  held  together  by  two  large  bolts  passing  through  the  T  piece, 


4IO 


MODERN   STEAM   PRACTICE. 


brasses,  and  cap.  This  is  a  neat  form  of  connection ;  whether  the 
brasses  have  a  plain  exterior  or  are  cut  out  in  the  pattern,  the 
bottom  part  is  generally  cored  out  to  save  weight  and  metal.  For 
trunk  engines  of  the  single  class  the  brasses  are  placed  in  a  pillow 
block,  cast  along  with  the  piston,  and  two  bolts  pass  through  the 
piston  for  securing  the  cap.  This  arrangement  is  adopted  for  forked 
connecting  rods;  but  for  single  connecting  rod  ends,  both  in  single- 
trunk  and  double-trunk  arrangements,  the  pillow  block  and  brasses 
are  dispensed  with,  and  a  crosshead  of  wrought  iron  is  substituted, 
with  bosses  forged  on  the  end,  through  which  it  is  securely  bolted 
to  the  trunk.  In  single-trunk  engines  raised  bosses  are  cast  on  the 
piston,  and  accurately  faced  for  fitting  against,  the  bolts  passing 
through  the  piston,  and  having  their  heads  covered  with  a  plate 
let  into  the  piston,  which  prevents  the  steam  escaping  through  the 
trunk  into  the  atmosphere ;  while  in  the  double-trunk  engine  the 
crosshead  is  secured  by  bolts  which  pass  through  snugs  cast  along 
with  the  trunk,  and  do  not  require  to  be  made  steam-tight,  as  in 
the  preceding  case.  The  snugs  should  be  strengthened  with  a  deep 
feather,  so  as  to  take  the  thrust  and  pull  which  is  transmitted  on 
all  connecting-rod  attachments. 

The  most  approved  form  of  connecting  rod  between  the  cross- 


Fig.  293. — Connecting-rod  End  for  Cranked  Shaft. 
A,  End  forged  on  the  piston  rod.     B,  Cap.     c  c,  Bolts  and  nuts.     D,  Brasses. 

head  and  cranked  shaft  is  that  with  solid  ends  forged  on,  slotted 
out  for  the  reception  of  the  brasses,  with  caps  of  wrought  iron 
secured  by  two  large  bolts.  The  part  for  taking  the  brasses  can 
be  bored  out,  the  bedding  forming  a  true  circle ;  the  ends  and  cap 
are  forged,  turned,  and  finished  entire,  with  holes  bored  for  the 
reception  of  the  bolts,  which  are  so  spaced  that  part  of  the  brasses 
require  to  be  scooped  out,  which  prevents  them  turning  round  in 


MARINE   ENGINES. 


411 


their  seats.  After  the  end  is  finished  it  is  slotted  across  the  middle, 
the  part  slotted  off  forming  the  cap;  the  brasses  have  the  usual 
flanges  all  round,  and  are  entirely  finished  in  the  turning  lathe. 
The  bolts  have  solid  heads,  with  part  of  the  nuts  recessed  into  the 
cap,  and  a  set  screw  passes  through  the  side  of  the  head,  pressing 
against  the  nut  to  prevent  it  becoming  loose ;  the  bolts  are  secured 
in  like  manner:  these  precautions  being  necessary  with  high-speed 


Fig.  294. — Connecting-rod  End  for  Cranked  Shaft. 
A,  End  forged  on  the  piston  rod.     B,  Cap.     c  c,  Bolts  and  nuts.     D,  Brasses. 

engines.  Some  engineers  prefer  to  have  a  flat  part  left  for  the 
sides  of  the  brasses,  made  deep  enough  to  take  a  part  of  the  top 
brass,  with  a  cap  of  sufficient  depth  to  suit  the  requirements;  the 
heads  and  nuts  of  the  bolts  are  not  generally  recessed  into  the 
block  and  cap,  but  the  nuts  are  turned  down,  leaving  a  hollow  part, 
and  a  washer  fitted  with  a  pin  in  the  cap,  with  a  set  screw  bearing 
in  the  groove  cut  out  in  the  nut  to  prevent  it  shaking  loose.  In 
some  examples  both  of  the  ends  are  forged  on  in  one  block;  and 
others  have  forked  ends  to  suit  the  crosshead  adopted,  having  a 
pin  securely  fastened  through  holes  bored  out  in  the  forked  ends, 
with  a  collar  at  one  end  and  a  pin  at  the  other  end  securely  rivetted 
in.  Other  forms  of  connecting  rods  have  T  pieces  forged  on  the  ends, 
with  brass  distance  blocks  between  the  T  piece  and  the  cap,  bolted 
together  with  two  bolts.  These  blocks  are  lined  with  white  metal, 
and  are  bored  out  to  suit  the  pin  on  the  cranked  shaft ;  the  end  for  the 
crosshead  does  not  require  white  metal  let  in.  In  some  cases  the 
blocks  are  made  quite  plain  and  flat  on  the  sides,  in  others  the 
pattern  is  cut  oyt  to  save  metal.  The  bolts  for  securing  the  brasses 
are  fitted  with  nuts  and  washers,  having  set  screws  for  preventing 
the  nuts  working  loose.  Sometimes  a  round  boss  is  left  on  the 
bottom  brass,   having  a  corresponding   hole   in  the  T  piece ;    this 


412 


MODERN   STEAM   PRACTICE. 


Fig.  29s. — Connecting-rod  End  for  Cranked  Shaft. 
A  A,  Brass  ends.  B,  Cap.  c  c,  Bolts  and  nuts. 
D,  T  piece  forged  on  the  piston  rod.     E,  Oil  cup. 


helps  to  take  the  side  strain  off  the  bolts,  but  the  generality  of 
makers  leave  these  surfaces  quite  plain.     When  the  bottom  end  of 

the  connecting  rod  is  con- 
nected to  a  journal  inside  of  a 
trunk,  it  is  necessary  that  the 
brasses  can  be  tightened  up 
from  the  outside,  and  for  this 
purpose  the  eye  of  the  rod  is 
forged  on  solid,  and  bored  and 
slotted  out  for  the  brasses; 
the  rod  is  then  bored  out  for 
nearly  its  entire  length,  for  the 
reception  of  an  inside  steel  bar, 
which  is  fitted  at  the  top  with 
a  cotter  for  tightening  up  the 
rod  against  a  steel  plate  let 
into  the  top  brass,  the  bottom 
brass  having  a  projection  cast 
on,  which  fits  into  the  central 
hole  in  the  connecting  rod.  This  is  a  neat  arrangement,  and  can- 
not be  dispensed  with  when  the  brasses  work  in  a  crosshead  held 

, 1, 1  quite  rigid. 

The  old  form  of  connecting 
rod,  with  straps,  jibs,  and  keys, 
may  in  some  instances  be  bene- 
ficially adopted,  more  especially 
for  the  crosshead  for  double 
piston-rod  return  connecting-rod 
engines;  in  this  arrangement, 
having  the  keys  passing  through 
a  slotted-out  part  left  in  the 
broad  rubbing  surface,  with  a 
groove  formed  in  the  condenser 
casting  for  the  end  of  the  key 
to  travel  backward  and  forward 
in,  the  distance  from  the  centre 
of  the  journal  of  the  crosshead 
to  the  plate  on  which  the  block 
slides  can  be  greatly  reduced,  which  is  a  somewhat  important  con- 
sideration,    A  very  simple  form  of  connecting  rod  has  half  brasses 


ng.  296. — Connecting-rod  End  for  Cranked  Shaft, 

A,  Rod.     B,  Butt,     c  c,  Strap,     d.  Brasses. 

E,  Jibs  and  cotters. 


MARINE   ENGINES. 


413 


at  the  top  and  bottom,  with  a  small  rod  on  each  side,  on  which  are 
left  collars  for  the  bottom  part  or  inside  brasses  to  bear  against, 
while  the  two  outside  brasses  are  bolted  hard  up  against  the  inside 
ones,  with  a  screwed  part  on  the  ends  of  the  rods  having  nuts  and 
washers:  these  rods  therefore  act  as  the  main  connecting  rod  and 
tightening-up  bolts.  This  plan,  however,  has  not  been  much 
adopted. 

The  next  detail  to  consider  is  the  cranked  shaft — a  term  adopted 
to  distinguish  between  cranks  forged  in  one  piece  with  the  shaft, 
and  plain  ones  having  cranks  shrunk  on.  The  crank  arms  are 
forged  on  solid  at  right  angles 
to  each  other,  they  are  then  bored 
across  and  slotted  out  for  the 
part  between  the  jaws,  leaving  a 
part  for  the  crank  pin,  which  is 
turned  out  in  the  turning  lathes 
or  cutting-out  machines  used  for 
that  purpose.  There  are  three 
main  bearings,  one  on  each  side 
of  the  cranks  at  the  outside 
and  one  central  bearing  between 
them.  When  the  distance  be- 
tween the  cylinders  is  great,  the 
cranked  shaft  is  separated  at 
the  centre  between  the  cranks, 
having  solid  discs  forged  on,  secured  with  bolts  and  nuts,  and  a 
cross  key  for  taking  the  sheering  strain  off  the  bolts:  in  this 
arrangement  two  central  bearings  are  provided,  instead  of  one, 
as  when  both  cranks  are  forged  on  entire.  The  end  parts  of 
the  crank  arms  are  often  finished  in  the  turning  lathe,  but  some 
examples  have  the  circular  form ;  the  former,  however,  is  the  better 
plan  when  counterweights  are  strapped  on  for  balancing  the  weight 
of  the  crank  arms.  These  straps  are  quite  flat,  except  where  they 
pass  through  the  cast-iron  balancing  piece,  where  they  are  rounded. 
The  balancing  piece  is  secured  with  nuts,  let  into  the  block  at  the 
extrem.e  end,  and  joggled  into  the  arms  at  the  crank  end ;  the  end 
of  the  strap  should  have  a  round  pin  rivetted  in,  with  a  correspond- 
ing hole  bored  on  the  crank  end,  which  tends  to  prevent  the  strap 
moving  sideways.  Some  makers  leave  a  joggle  on  each  side  of 
the  strap  by  planing  out  the  sides  of  the  crank  arm,  which  makes 


Fig.  297. — Cranked  Shaft 
A  A,  Cranked  shaft.     B,  Main  bearing,    c,  Crank  pin. 


414 


MODERN    STEAM    PRACTICE. 


Balance  and  Cranked  Shaft. 

C  c.  Balances. 


A  A,  Cranked  shaft.     B,  Crank  pin, 
DD,  Straps. 


a  first-class  piece  of  work,   effectually  preventing   these  balance 
weights  moving  sideways.     The  crank  arms  in  some  cases  taper 

from  the  shaft  to  the  crank- 
pin  bearing,  in  others  they  are 
left  parallel ;  and  when  other 
modes  of  balancing  the  cranks 
and  connecting  rods  are  adop- 
ted, the  corners  of  the  cranks 
can  be  finished  to  a  bold  radius, 
by  which  part  of  the  weight  re- 
quiring balancing  is  removed. 
The  journals  for  the  cranked 
shaft,  and  indeed  all  journals, 
should  be  finished  with  the 
tool  in  the  lathe;  the  use  of  emery  to  get  up  a  smooth  face  is  a 
practice  long  ago  exploded,  and  rightly  so,  as  many  journals  and 
bearings  have  been  torn  and  rutted  up  by  the  fine  particles  of 

emery  indented  in  the  iron.  All 
the  collars  should  be  turned 
with  a  bold  radius,  for  when 
they  are  left  square  it  is  gen- 
erally here  that  the  shaft  gives 
way  after  long  use.  As  the 
strain  imparted  from  the  thrust 
and  pull,  passing  from  the 
piston  through  the  rods,  is 
both  rapid  and  severe,  this 
accident  may  occur  with  the 
best  arrangements;  it  is  there- 
fore always  advisable  to  have 
a  spare  cranked  shaft  stowed 
on  board  the  ship. 

What  are  called  built  shafts 
are  those  in  which  the  crank 
and  crank  pins  are  shrunk  on. 


4)  IQ 


OB 

Fig.  299. — Main  Framing  of  X  Section. 

A,  Main  frame.     B,  Brasses,     c,  Cap.     D  D,  Cotter      A     firC,     generally    of     WOOd,     is 
bolts  and  nuts.       E  E,  Flanges  for  bolting  to  cylinder.     1  •     1         j  ■•       ■, 

F,  Flange  for  bolting  to  condenser.   G,  Oil  cup.       hghtcd  Tound  the  cranks,  and 

when  sufficient  expansion  has 
taken  place  the  parts  are  slipped  into  position.  The  crank  on 
cooling  down  grips  the  shaft  and  pin  tightly. 


MARINE   ENGINES. 


415 


-^-i- 


•a  '2 


Fig.  298A  shows  the  crank  shaft  of  the  screw  steamer  Arizona.    It 

is  built  up  of  five  pieces.  Of  these 
four  are  made  of  hammered  and 
rolled  scrap  iron,  the  fifth,  or  crank 
pin,  being  made  of  steel.  The  dia- 
meter is  22^  inches. 

The  immense  power  of  engines  in 
some  of  the  recently  launched  ocean 
steamships  for  the  Atlantic  service 
necessitates  correspondingly  heavy 
and  strong  machinery;  thus  the 
crank  shaft  of  the  Se7^via,  City  of 
Ro7ne,a.ndA/askaa.rea.bout  25  inches 
in  diameter;  those  of  the  Senna  and 
Alaska  are  solid,  whilst  that  of  the 
City  of  Rome  is  hollow.  This  shaft  is 
of  steel  and  made  by  Sir  J.  Whit- 
worth's  process,  the  steel  being 
known  as  fluid  compressed,  this  me- 
thod being  adopted  to  insure  uni- 
formity in  structure.  The  process 
consists  in  first  of  all  casting  the  steel 
in  a  mould  having  a  core;  thereafter, 
andwhilestill  fluid, thecasting  is  sub- 
jected to  an  intense  hydraulic  pres- 
sure, which  forces  the  air  and  gaseous 
matters  out  of  the  fluid  mass.  After 
solidifying  the  metal  is  reheated  and 
forged  down  to  a  length  suitable  for 
the  purpose  for  which  it  is  to  be  ap- 
plied. A  stronger  shaft  for  the  same 
weight  of  metal  is  thus  obtained. 

The  main  framing  (Fig.  299)  on 
which  the  pillow  blocks  are  cast  for 
sustaining  the  cranked  shaft  may  be 
regarded  as  the  backboneof  horizon- 
tal marine  engines.  It  is  subjected  to 
tensional,  compressive,  and  twisting 
strain,  and  must  therefore  be  made 
of  great  strength.    Some  makers  adopt  the  i  section,  others  the  -|-, 


i._.^._. 


.-o 


41(5 


MODERN   STEAM   PRACTICE. 


while  some  consider  the  box  form  preferable ;  and  all  these  forms  are 
successfully  carried  out  in  practice.  Strength  is  the  main  thing  to  be 
looked  to;  but  the  open  form  of  framing  has  the  advantage  of  giving 
more  convenient  access  to  the  various  glands.  The  frame  is  firmly 
bolted  to  the  cylinder  at  the  top  and  bottom,  and  also  to  a  flange 
carried  along  from  the  cylinder  to  the  condenser.     This  flange  is 


^      II      f 


Fig.  300. — Main  Framing  of  +  Section. 

A,  Frame,     b.  Brasses,     c.  Cap.     d  d,  Bolts  and  nuts,     e  e,  Flanges  for  bolting  to  cylinder. 
F,  Flange  for  bolting  to  condenser. 

secured  to  the  keelson  or  engine  bearers  by  long  bolts  passing 
down  to  the  under  side  of  the  bearers,  with  cross  bars  of  cast  iron 
at  the  under  side ;  in  this  way  the  whole  depth  of  the  engine  bearer 
is  secured.  All  the  bolt  holes  should  have  proper  bosses  cast  on 
the  framing,  to  suit  the  bottom  and  other  flanges  connected  to  the 
cylinder  and  condenser,  so  that  a  fair  bed  for  the  nuts  can  easily 
be  faced  up.  The  brasses  for  the  pillow  blocks  are  fitted  just  as  in 
any  other  arrangement  lying  on  its  side,  and  are  secured  by  caps 
of  cast  or  wrought  iron;  each  cap  has  two  large  bolts  passing 
through  it  into  holes  cast  and  bored  out  in  the  casting,  and  fastened 
with  cotters.  The  cap  is  fitted  with  clips  at  the  top  and  bottom,  nicely 
fitted  to  the  pillow  block,  to  prevent  its  sides  springing;  and  the 
nuts  for  the  bolts  are  fitted  with  washers  and  set  pins,  to  prevent 
them  becoming  loose.     All  the  work  connected  with  the  pillow 


MARINE   ENGINES. 


417 


blocks  must  be  well  executed,  for  the  main  stress  is  directly  taken 
on  these  bearings.  When  the  distance  between  the  cylinders  is 
great,  leaving  a  long  centre  part  on  the  cranked  shaft  between  the 
cranks,  the  centre  bearing  should  be  increased  in  length,  so  that  no 
undue  strain  is  taken  on  the  cranked  shaft;  in  fact,  the  shaft  should 
be  always  supported  as  close  to  the  cranks  as  is  practicable.  All 
the  brass  bearings  are  recessed  for  the  reception  of  white  metal, 
which  is  poured  in  while  in  a  fluid  state,  a  cast-iron  core  piece, 
somewhat  less  than  the  diameter  of  the  shaft,  being  first  inserted 


Fig.  301. — Main  Framing  of  Box  Section. 

A,  Frame.     B,  Brasses,     c,  Cap.     d  d.  Bolts  and  nuts.     E,  Wrought-iron  stay.     F,  Slipper  guide. 

G,  Oil  cup. 

in  the  bearing,  so  as  to  keep  the  white  metal  in  its  place;  the  half 
brasses  are  held  together  prior  to  this  operation,  and  are  bored  out 
in  the  lathe  and  then  separated.  In  this  way  fair  work  is  secured ; 
but  some  makers  prefer  boring  out  the  brasses  in  situ,  and  no 
doubt  when  properly  executed  this  plan  has  its  advantages.  In 
most  machinery  there  are  numerous  fittings  which  can  be  con- 
veniently cast  on  the  main  framing,  or  bolted  on  fitting  strips  left 
for  that  purpose;  and  proper  attention  to  these  points  shows  the 
skilfulness  of  the  designer,  and  saves  much  work  afterwards. 

The  box  form  of  framing  differs  materially  from  the  i  and  + 

27 


4i8 


MODERN   STEAM   PRACTICE. 


sections,  although  the  brasses  are  also  fitted  in  lying  on  their  side, 
in  order  to  adjust  them  in  a  direct  line  with  the  strain  given  off  from 
the  piston.  The  part  of  the  bottom  frame  which  forms  the  con- 
nection between  the  cylinder  and  the  condenser  is  retained,  but  the 
top  part  is  dispensed  with,  and  a  wrought-iron  stay  introduced, 
keyed  through  a  boss  bored  out  for  its  reception  in  the  head  or 
pillow  block ;  on  the  other  end  of  this  stay  a  flange  is  formed  for 
securing  it  by  bolts  and  end  keys  to  the  cylinder  at  the  side  of  the 
steam  jacket.  Between  the  bottom  part  of  the  framing  and  the 
cylinder  a  bed  plate  is  introduced,  on  which  raised  parts  are  cast 
to  receive  what  is  termed  the  slipper  guide  plate  for  the  crosshead 
of  direct-acting  single  piston-rod  arrangements.  This  part  of  the 
framing  extends  across  the  engine,  embracing  all  the  pillow  blocks 
for  carrying  the  cranked  shaft,  which  blocks  are  also  cast  entire 
along  with  the  bottom  frame  plate;  but  at  the  condenser  end  parts 
are  cut  out  in  the  bottom  having  merely  projections  opposite  the 
bearings  for  bolting  to  the  condenser.  This  form  of  framing 
has  a  strong  yet  light  appear- 
ance, and  cannot  be  excelled 
for  the  peculiar  type  of  engine 
for  which  it  is  designed,  as  all 
the  parts  are  easily  reached — 
a  great  desideratum  in  the 
marine  engine;  while  the  whole 
framework  is  firmly  united  to 
the  keelsons  by  one  broad  base 
plate. 

In  another  form  of  framing, 
Fig.  302,  we  have  the  means  of 
tightening  up  the  main  brasses 
by  wedge  pieces  let  into  the 
pillow  blocks.  This  frame 
extends  from  the  cylinder  to 
the  condenser,  with  ribs  and 
feathers  cast  along  with,  and 
in  a  direct  line  with  the  sides 
of  the  pillow  block  or  bearing  piece,  the  cap  for  holding  down 
the  brasses  being  placed  on  the  top,  instead  of  on  the  side  as  in 
the  previous  examples.  Between  the  brasses  at  the  cylinder  end 
two  wedge  pieces  of  wrought  iron  are  introduced,  extending  across 


Fig.  302.— Main  Framing  with  Adjusting  Wedges. 

A,  Frame,     b,  Brasses,     c,  Cap.     d  d,  Bolts  and  nuts. 
E  E,  Adjusting  wedges.     F,  Oil  cup. 


MARINE  ENGINES.  419 

between  the  flanges,  having  a  spindle  forged  on,  and  passing 
through  the  cap ;  they  have  a  screw  cut  on  the  end  with  nut  and 
lock  nut  fitted,  by  which  means  the  brasses  can  be  tightened  up  or 
adjusted  at  any  time.  In  other  arrangements  a  single  wedge  piece 
is  introduced,  having  one  central  spindle  fitted  with  two  nuts  for 
tightening  up  against  the  cap.  Some  makers  introduce  the  brasses 
in  four  parts,  one  at  each  side  and  one  at  the  top  and  bottom ;  by 
this  means  they  can  be  adjusted  vertically  and  longitudinally. 

The  condenser. — We  now  come  to  consider  the  arrangements  for 
efifetting  the  condensation  of  the  steam  with  ordinary  injection 
condensers.  All  condensing  vessels  should  be  constructed  as  simply 
as  possible ;  and  the  arrangement  of  the  water  pipes  leading  into 
and  from  them,  as  well  as  valve  seats,  discharge  chambers  or  hot 

wells,  and  all  their  vari- 
ous fittings,  requires 
careful  consideration. 
Where  large  flat  sur- 
faces are  required,  they 
should  be  well  strength- 
ened with  ribbed  bars 
in  the  casting;  some 
makers  use  wrought- 
Fig.  303.— Exhaust  Pipe.  iron  stays,  which  tend 

A,  Pipe.     B,  Stuffing  box  and  gland,     c,  Baffle  plate.  P"reatlv      tO     StrcnS'thcn 

D,  Condenser.       E,  Hole  for  running  off  condensed  steam. 

the  condensing  vessel 
against  collapsing.  The  other  parts  of  the  general  casting  must  be 
well  bound  with  the  various  divisions  required  for  the  air  pump  and 
valve  fittings.  The  capacity  of  the  condenser  is  greatly  affected 
by  the  size  of  the  exhaust  pipe  from  the  cylinder;  this  pipe  should 
have  a  large  area,  so  as  to  freely  pass  the  steam  to  that  part  of  the 
condenser  where  the  water  from  the  sea  is  showered  in ;  thus  the 
large  pipe  receives  the  steam,  which  is  at  once  condensed,  and  the 
capacity  of  the  condensing  vessel  need  not  be  so  large  as  when  the 
exhaust  steam  finds  its  way  into  a  condenser  placed  alongside  of 
a  cylinder  having  no  pipe  connection. 

The  exhaust  pipe  should  be  fitted  with  an  expansion  joint,  which 
is  generally  placed  on  the  condenser  casting,  the  end  of  the  pipe 
passing  through  a  loose  hoop  placed  at  the  bottom  of  the  stuffing 
box;  by  this  means  the  pipe  can  be  angled  into  its  place  without 
disturbing  the  cylinder  or  condenser.     The  loose  hoop  and  gland 


420  MODERN   STEAM   PRACTICE. 

being  placed  on  the  pipe  in  the  first  instance,  the  hoop  is  then 
shpped  into  its  place,  and  the  gland  pressed  down  on  the  hemp 
packing  in  the  usual  manner;  the  other  end  of  the  pipe  is  secured 
by  a  flange  bolted  to  the  cylinder.  There  are  also  other  forms  of 
expansion  joints.  Some  have  hollow  discs  formed  on  the  body  of 
the  pipe,  with  end  flanges  for  securing  the  pipe  to  the  cylinder  and 
condenser,  thus  forming  a  rigid  stay  between  the  two,  but  having 
the  power  of  expanding  by  compressing  the  flat  discs,  and  con- 
tracting when  the  strain  is  off  by  opening  the  disc  plates.  We 
prefer,  however,  the  usual  mode  with  stuffing  box  and  gland.  The 
position  of  the  condensing  chambers  varies,  and  depends  greatly  on 
the  location  of  the  air  pumps.  When  these  are  placed  together,  one 
on  each  side  of  the  middle  frame  for  carrying  the  cranked  shaft, 
the  condensers  are  then  generally  in  a  line  with  the  outer  frames,  or 
fore  and  aft  of  the  outer  lines  of  the  cylinders.  In  return  connect- 
ing-rod engines,  with  the  discharge  chambers  placed  between  the 
centre  lines  of  the  cylinders,  and  in  similar  arrangements  of  air 
pumps,  the  condensing  chamber  and  discharge  chambers  are  both 
placed  between  the  centre  lines  of  cylinders;  this  plan  necessitates 
the  cylinders  to  be  placed  further  apart  from  centre  to  centre — that 
is  to  say,  when  the  air  pumps  are  located  at  the  side  of  the  motion 
or  guide  bars  for  the  crosshead.  Sometimes  the  air  pumps  are 
arranged  underneath  the  motion  bars,  having  the  discharge  chamber 
at  the  middle  between  them,  and  the  condensing  chambers  on  each 
side;  while,  in  other  examples,  with  one  air  pump  on  the  outside 
of  each  outer  frame,  fore  and  aft,  the  condensing  chamber  and 
discharge  chamber  are  cast  together  immediately  over  the  air  pump. 
In  direct-acting  single  piston-rod  and  double-trunk  engines,  the 
air  pumps  are  always  placed  one  on  each  side  of  the  centre  frame, 
having  the  condensing  and  discharge  chambers  located  immediately 
above  them;  while  in  plunger  air  pumps  with  single-acting  arrange- 
ments for  foot  and  head  valves,  suited  for  single  trunk  and  return 
connecting-rod  engines,  the  condensing  and  discharge  chambers 
are  placed  immediately  over  the  pumps. 

The  general  arrangement  of  all  these  forms  of  condensers, 
exhaust,  discharge,  and  injection  pipes,  air  pumps,  with  foot  and 
head  valves,  &c.,  cast  in  one  or  more  castings,  is  as  follows.  When 
the  air  pumps  are  arranged  one  on  each  side  of  the  middle  frame, 
there  are  generally  two  separate  castings,  all  the  fittings  for  which 
are  kept  quite  independent     The  air  pump  in  all  the  examples 


MARINE   ENGINES. 


421 


Fig.  304. — Air  Pump  with  Condenser  outside  and 
Discharge  Chambers  at  centre. 

A,  Condenser.     B,  Hot  well,   c,  Foot-valve  seat. 
D,  Head-valve  seat.      e  e,  Guide  bars.      F,  Air  pump. 


under  notice,  whether  fitted  with  an  internal  plunger  or  a  simple 
piston,  is  of  the  double-acting  type,  and  is  worked  directly  off  the 
steam  piston  by  means  of  a  rod  connected  to  it,  having  packing 

glands  on  cylinder  end  and 
air-pump  cover.  When  the 
pumps  are  placed  as  above 
i  described,  the  foot  valves  are 
underneath  and  the  head 
valves  above  them ;  there  are 
separate  chambers  for  the 
foot  valves  at  each  end,  but 
the  head  valves  are  fitted  in 
one  chamber  common  to  both 
ends.  Doors  for  the  foot 
valves  are  fitted  at  each  end, 
one  of  which  forms  the  cover, 
and  the  other  is  an  ordinary 
door;  on  each  of  these  doors  a  circular  pipe  piece  is  cast,  for  filling 
up  the  space  above  the  foot  valves,  so  as  not  to  leave  so  much  dead 
water  in  the  foot-valve  chambers.      The  doors  on  the  discharge 

chamber  containing  the  head  valves 
are  of  the  ordinary  description ; 
these  as  v/ell  as  the  other  doors  are 
generally  bolted  by  stud  bolts  and 
nuts.  Two  deep  feathers  are  cast 
along  with  the  hot  well,  which  forms 
an  air  chamber  tending  to  relieve 
the  shock  caused  by  the  rapid  dis- 
charge of  the  water.  The  discharge 
pipe  is  fitted  to  one  end  of  the 
hot  well,  at  the  top,  and  is  placed 
in  communication  with  one  pipe 
overboard  common  to  both  air 
pumps.  The  condensing  chamber 
is  on  the  opposite  side  of  the  centre 
line  of  the  cylinder  in  regard  to  the  air  pump,  the  exhaust  comes 
in  at  the. top,  and  the  injection  pipe  immediately  under  it.  The 
condensing  chamber  is  ribbed  and  cast  with  circular  parts,  which  are 
bored  out  for  the  reception  of  the  air-pump  barrels ;  these  are  cast 
in  brass,  and  fitted  with  solid-ended  pistons  of  the  same  material. 


f<-t"—""'4 


Fig.  305. — Air  Pumps  with  Condenser  and 
Discharge  Chamber  at  centre. 

A,  Condenser.    B,  Hot  well,    c,  Foot-valve  seat. 

D,  Head-valve  seat.     E,  Guide  for  piston-rod 
crosshead.      f,  Air  pump,     g.  Discharge  pipe. 


422 


MODERN    STEAM   PRACTICE. 


The  snifting  valve  for   all  condensers  is  fitted  as  low  down  as 
possible. 

For  similar  arrangements  of  air  pumps  situated  on  each  side  of 
the  middle  frame,  the  foot  valves  are  placed  low  down  on  the  other 
side  of  the  centre  line  of  the  cylinder  in  regard  to  the  air  pump, 
with  the  head  valves  in  one  chamber  common  to  both,  arranged 
between  the  air  pumps;  the  doors  for  getting  at  the  valves  are 
placed  on  the  top  of  the  valve  chambers,  which  is  found  a  very  con- 
venient and  handy  arrangement  One  discharge  pipe,  placed 
centrally  with  the  hot  well,  serves  for  both  of  the  pumps.  The 
exhaust  steam  comes  in  at  the  top  end  of  the  chamber,  and  the 
water  falls  down  underneath  the  air  pumps,  the  condenser  being 
partly  above   and  partly  below     ______ 


Fig.  306. — Air  Pump  with  Condenser  outside  fitted  with 
inverted  Foot  Valves  and  Discharge  Chamber  at 
centre. 

A,  Condenser.     B,  Hot  well.     C,  Foot-valve  seat. 
,  u       D,  Head-valve  seat.      e  e,  Guide  bars  for  piston-rod 
crosshead.     F,  Air  pump.     G,  Discharge  pipe. 


the  pumps,  and  having  a  divi- 
sion cast  in  for  separating  and 
strengthening  it.  The  injection 
valve  can  be  placed  above  the 
exhaust  pipes,  and  thus  shower 
the  injection  water  down  on  the 
steam,  instead  of  meeting  it  as 
in  the  previous  example. 

When  the  air  pumps  are  situ- 
ated underneath  the  motion  bars, 
a  good  plan  is  to  invert  the  foot 
valves,  placing  them  in 
bottom  of  the  condensers,  which 
are  seated  in  a  line  with  the  outside  frame;  thus  the  condensing 
water  and  the  condensed  water  from  the  steam  fall  into  each 
suction  chamber  by  their  own  gravity.  In  this  arrangement  the 
head  valves  are  placed  in  a  central  chamber  between  the  pumps; 
and  this  chamber  has  one  discharge  pipe  common  to  both  sets 
of  air  pumps.  The  exhaust  steam  enters  at  the  top,  the  injec- 
tion pipe  is  placed  under  and  showers  the  water  upwards  to 
meet  the  steam,  care  being  taken  that  the  water  cannot  pass 
into  the  exhaust  pipe.  The  injection  pipe,  when  placed  below  the 
exhaust  pipe,  should  always  be  pierced  with  holes,  to  shower  the 
condensing  water  meeting  the  steam,  instead  of  pouring  it  down 
vertically ;  by  this  means  the  water  and  steam  are  brought  into 
better  contact,  and  form  a  more  rapid  vacuum. 

When  the  air  pumps  and  condensers  are  arranged  in  a  line  with 


MARINE   ENGINES. 


423 


the  outside  frames,  the  foot  valves  are  inverted,  the  head  valves 
being  over  the  pump,  with  a  discharge  chamber  and  pipe,  having 
the  condenser  immediately  over  it,  separated  by  means  of  division 
plates  in  the  casting;  the  exhaust  pipe  is  placed  at  one  side,  and 
the  injection  pipe  on  the  opposite  side  arranged  for  showering  the 
water  downwards.  A  bed  plate  for  carrying  the  guides  for  the 
crossheads,  &c.,  lies  between  the  two  pumps,  and  forms  a  very 
convenient  starting  platform,  nearly  on  a  level  with  the  engine  floor 
plate.  Some  engineers,  however,  make  use  of  this  space  for  arrang- 
ing the  condensing  chambers  between  the  guide  bars,  with  the  air 
pumps  placed  as  before  inside  of  the  outer  frames.     The  foot  valves 

are  placed  at  the  bottom  and 
side  of  the  air  pump,  and  the 
head  valves  immediately  over 
them,  with  side  doors  to  each, 
and  a  discharge  pipe  for  the 
pump.  The  exhaust  pipes 
enter  at  the  top  of  the  cen- 
tral condensing  chambers, 
and  the  injection  pipes  are 
placed  lower  down.  It  is  ad- 
visable with  this  form  of  con- 


Fig  307. — Air  Pump  with  Condenser  outside  fitted  with     (JgnSCr    at  IcaSt  for  eno"ineS  of 
inverted  Foot  Valves  and  Discharge  Chamber  outside, 
all  in  one  casting. 

A,  Condenser.     B,  Hot  well,      c,  Foot-valve  seat. 
D,  Head-valve  seat.     E  E,  Guide  bars  for  piston-rod  cross- 
head.     F,  Air  pump.     G,  Exhaust  pipe. 


great  power,  that  the  pumps 
should  be  separate  castings; 
provision  should  also  be  made 
on  the  patterns  for  attach- 
ing and  fitting  to  the  general  casting  the  feed  and  bilge-water 
pumps,  which  are  generally  worked  off  arms  keyed  on  the  piston 
rods,  or  with  studs  fitted  to  the  crossheads,  or  even  with  direct  rods 
from  the  steam  piston.  We  have  here  given  examples  of  condensers 
with  their  adjuncts  which  are  in  general  use;  but  it  will  be  under- 
stood that  a  variety  of  forms  can  be  arranged  for  return  connecting- 
rod  engines. 

We  now  turn  to  arrangements  that  have  been  adopted  for  direct- 
acting,  single  piston-rod,  and  double  trunk  engines.  There  is  a 
great  similarity  in  the  various  parts  of  these,  chiefly  owing  to  the 
air  pumps  being  located  one  on  each  side  of  the  middle  frame  for 
carrying  the  cranked  shaft.  The  condenser  is  situated  centrally 
above  the  pumps,  having  the  foot  valves  inverted,  so  that  the  water 


424 


MODERN    STEAM    PRACTICE. 


—Air  Pumps  with  Condenser  at  centre 
fitted  with  inverted  Foot  Valves  and  Dis- 
charge Chambers  at  side,  all  in  one  casting. 

A,  Condenser.      B,  Hot  well,      c.  Foot-valve 

seat.     D,  Head-valve  seat.     E,  Air  pump. 

F,  Feed  pump,     g,  Exhaust  pipe. 


falls  into  the  pump  chamber  by  gravitation ;  the  head  valves  are 
placed  at  the  side  and  above  the  line  of  foot  valves,  with  a  hot  well 
for  each  pump  fitted  with  separate 
discharge  pipes  overboard.  With  this 
arrangement  of  foot  and  head  valves 
air  is  not  so  liable  to  collect  between 
the  piston  and  valves ;  it  is  therefore 
preferable  to  have  an  air  valve — 
should  it  be  desirable  to  place  the 
discharge  valves  below  the  line  of 
head  valves — arranged  at  the  highest 
point  in  the  foot-valve  chamber,  by 
which  the  air  is  forced  into  the  dis-  Fi 
charge  pipe  overboard.  The  exhaust 
pipe  is  of  a  large  diameter,  suited  for 
both  engines,  placed  in  the  centre  of 
the  condenser,  and  the  injection  pipe 

is  placed  at  the  top  on  the  same  centre  line,  thus  the  water  is 
showered  down  on  each  side  of  the  condensing  chamber:  this 
arrangement  is  very  effective.  In  other  arrangements  the  valves 
are  placed  vice  versa,  the  condensing 
chambers  being  at  the  side,  and  the  dis- 
charge chamber  placed  centrally  above 
the  pumps,  with  one  discharge  pipe 
overboard ;  while  there  are  two  exhaust 
pipes,  each  passing  into  a  separate  con- 
denser, with  the  injection  pipes  under- 
neath. This  arrangement  has  the  ad- 
vantage of  the  condensers  for  the  cylin- 
ders being  separate  from  each  other, 
and  this  enables  us  to  regulate  the  in-  Fig.  309. -Air  Pump  with  Condenser  at 

■^  1   .    1  ^''^^  fitted  with  uiverted  Foot  Valves  and 

jection    water    required     by  each,     which        Discharge  chamber  at  centre. 

we  cannot  do  when  one  injection  pipe  a,  condenser,  b,  Hotweii.  c,  Foot-vaive 

.  seat.     D,  Head-valve  seat.    E,  Air  pump. 

serves  for  both  condensers.    These  con-       p,  Feed  pump,  g,  Exhaust  pipe, 
densers,  when  required   for  engines  of 

ordinary  power,  are  generally  cast  in  one  piece,  but  for  heavy 
engines  they  should  be  two  separate  castings,  with  air  pump  and 
adjuncts  arranged  as  in  the  previous  examples. 

The  Surface  System  of  Condensation.— Before  describing 
the  construction  of  the  condenser  for  the  surface  system  of  con- 


MARINE   ENGINES.  425 

densation,  we  shall  notice  the  disadvantages  attending  the  injection 
system  for  the  condensing  of  steam  in  marine  engines.  The  chief 
objection  doubtless  arises  from  the  necessity  for  using  a  continuous 
supply  of  salt  water  in  the  boilers,  the  salt  accumulating  to  such 
an  extent  that  a  high  degree  of  heat  is  required  to  raise  the  steam. 
This  accumulation  of  salt  proceeds  so  rapidly,  that  it  is  necessary 
to  blow  off  the  water  in  the  boiler  every  two  hours  or  so,  the  feed 
from  the  hot  well  at  the  same  time  is  turned  on,  thus  the  hot  brine 
being  blown  off,  and  replaced  with  a  colder  fluid,  the  temperature 
of  the  water  in  the  boiler  is  greatly  reduced,  and  requires  much 
valuable  fuel  to  keep  it  up  to  the  proper  working  point.  The  rapid 
incrustation  that  takes  place  is  likewise  a  serious  objection,  as  the 
scale  formed  all  round  the  parts  immediately  exposed  to  the  action 
of  the  flame  is  a  very  bad  conductor  of  heat,  and  not  only  impedes 
the  free  transmission  of  the  heat  to  the  water,  but  in  many  parts 
of  the  boiler  it  forms  to  such  an  extent  that  rupture  of  the  plates 
takes  place,  more  especially  on  the  back  parts  of  the  furnaces  where 
the  flame  returns  through  the  tubes — necessitating  frequent  inspec- 
tion, for  the  purpose  of  cleaning  the  boilers,  and  removing  the 
incrustations,  so  as  to  prevent  the  plates  wearing  out  too  rapidly. 
In  fact,  for  the  high-pressure  compound  engine  system,  the  injection 
condenser  has  been  discarded,  because  distilled  water  is  preferable 
to  impure  salt  water;  and  with  proper  precautions  we  can  safely 
adopt  high-pressure  steam  with  fresh  water,  and  thereby  save  much 
valuable  fuel. 

The  action  of  surface  condensation  may  be  familiarly  illustrated 
by  the  well  known  deposition  of  moisture  on  the  windows  of  a 
crowded  room,  due  to  the  cooling  surface  of  the  glass.  So  with 
the  steam  from  the  cylinder:  surface  must  be  provided,  and  cold 
must  be  applied  to  that  surface,  so  that  with  cold  on  the  one  side, 
and  the  steam  impinging  against  the  cold  surface  on  the  other,  the 
caloric  is  extracted,  and  water  flows  down,  similar  to  that  on  the 
window.  Thus  when  the  boilers  are  provided  in  the  first  instance 
with  pure  water,  it  is  used  over  and  over  again,  with  just  sufficient 
water  injected  from  the  sea  to  meet  the  waste,  and  keep  the  density 
of  the  water  in  the  boiler  at  about  the  same  as  the  water  in  the 
ocean,  this  being  considered  in  practice  very  safe.  And  as  water 
requires  a  large  surface  in  the  boiler  for  the  heat  to  act  upon  it  in 
raising  steam,  so  in  condensing  the  steam  rapidly  we  must  have  a 
large  amount  of  cold  surface  for  it  likewise.    The  surface  condenser 


426  MODERN    STEAM   PRACTICE. 

is  simply  an  arrangement  of  tubing  placed  in  a  convenient  vessel 
surrounded  with  water;  in  some  cases  the  tubes  are  filled  with 
water,  in  others  the  water  in  the  vessel  flows  all  round  their  exter- 
nal surface.  This  water  must  be  kept  constantly  flowing  through 
the  vessel,  so  as  to  maintain  the  refrigerating  surface  at  a  proper 
working  temperature.  For  this  purpose  a  circulating  pump  is 
fitted,  which  draws  the  water  through  the  tubes  or  around  them, 
as  the  case  may  be;  in  other  arrangements  the  water  is  forced 
through  or  amongst  the  tubes.  The  water  from  the  condenser  is 
carried  off  by  an  air  pump  similar  in  construction  to  that  used  for 
ordinary  injection  condensers,  and  is  delivered  into  a  separate 
vessel,  from  which  it  is  pumped  into  the  boilers,  in  some  instances 
directly  by  the  air  pump,  but  usually  feed  pumps  are  fitted  for  the 
purpose.  In  some  convenient  part  of  the  condenser  a  valve  and 
inside  pipe  are  fitted,  perforated  with  slits  or  holes  for  showering 
into  the  condenser  the  sea  water  necessary  to  keep  up  the  requisite 
amount  of  feed  for  the  boiler. 

We  now  come  to  consider  the  manufacture  and  arrangement  of 
surface  condensers.  The  tubes  vary  from  yi  inch  to  T/z  inch  internal 
diameter,  thickness  about  -J^  inch;  generally  ^  inch  outside  dia- 
meter; they  are  made  of  composition  metal,  and  are  known  by  the 
name  of  cold-drawn  composition  tubes.  The  tubes  for  government 
contracts  are  tinned  outside  and  inside  to  prevent  chemical  action. 
They  are  9  feet  long. 

The  tube  plates  are  of  copper,  and  vary  in  thickness  from 
•jSg-  inch  to  \%  inch ;  they  are  fitted  to  plane  surfaces  on  the  casting 
forming  the  vessel  containing  the  tubes,  and  are  secured  with  com- 
position metal  bolts  and  nuts.  A  variety  of  plans  are  adopted  for 
making  the  ends  of  the  tubes  air  and  water  tight.  The  original  plan 
(Fig.  310),  still  much  used,  consists  in  forming  screwed  stuffing  boxes 
in  the  tube  plate,  the  packing  being  a  tape  of  cotton  or  linen  sewn 
together,  which  is  slipped  over  the  ends  of  the  tubes,  and  pressed 
into  the  stuffing  box  with  a  screwed  gland.  These  glands  are 
manufactured  from  solid  rolled  tubes  of  composition  or  Muntz 
metal,  and  can  be  obtained  of  suitable  lengths;  the  inside  diameter 
must  slip  easily  over  the  tubes  in  the  condenser,  while  the  thickness 
is  regulated  by  the  size  of  the  gland,  so  that  a  proper  thread  is  cut 
in  a  similar  way  to  bolts  in  the  common  screwing  machine;  they 
are  cut  off  into  proper  lengths  by  a  circular  saw,  and  notched  in  a 
machine  with  two  notches,  for  screwing  them  into  the  stuffing  box 


MARINE   ENGINES. 


427 


Fig.  310. — Tape  Packing  for  Tubes. 
A,  Tube.     B,  Packing  gland. 


with  a  screw  driver.     Another  mode  of  making  the  tube  joints  is 
with  a  sheet  of  india  rubber  having  holes  suited  to  the  pitch  of  the 

tube.  The  holes  are  left  smaller  than 
the  outside  diameter,  and  when  the  tubes 
are  all  in  position,  being  merely  passed 
through  plain  holes  drilled  in  the  tube 
plates,  the  india-rubber  sheet  is  laid  over 
them,  and  an  outside  plate  is  bolted  up 
against  it,  which  plate  is  recessed  for  the 
reception  of  the  tubes,  and  leaves  a 
narrow  edge  round  each  tube ;  thus  with 
the  pressure,  and  the  holes  in  the  india 
rubber  being  much  smaller  than  the 
diameter  of  the  tube,  a  raised  flange  of 
india  rubber  is  formed  around  each  tube, 
and  the  tubes  are  gripped  by  an  elastic 
medium,  while  the  pressure  transmitted 
through  the  plate  by  the  bolts  to  the 
flat  surface  of  the  india  rubber  keeps  it 
in  perfect  contact  with  the  plate,  and  a 
good  joint  is  obtained.  Some  engineers,  however,  think  that  each 
tube  should  be  made  air  and  water  tight  separately,  so  that  if  a 
joint  gets  out  of  order  it  can  be  repaired  without  disturbing  the 

whole  series;  besides  with  such 
thin  tubes  it  is  an  object  to  have 
the  joint  elastic,  so  that  the  tubes 
can  expand  and  contract  easily. 
With  these  objects  in  view  the 
author  has  arranged  a  packing  ring 
of  a  peculiar  construction.  The 
holes  in  the  tube  plate  are  bored 
parallel,  and  then  tapped ;  a  gland 
or  screwed  nut  having  a  recess  for 
a  ring  of  india  rubber  or  any  other 
elastic  medium  is  fitted  to  each 
hole.  The  india  rubber  ring  is  a 
good  fit  in  the  recess,  and  is  put  in  place  by  merely  squeezing 
it  together;  its  inside  diameter  is  made  smaller  than  that  of  the 
tube,  according  to  the  amount  of  grip  required;  and  to  facili- 
tate the  operation  of  tubing,   a   loose   cone   plug   is  inserted  in 


Fig.  311.  — Sheet  mode  of  making  the  Tubes  tight. 
A  A,  Tubes.     B,  India-rubber  sheet,    c,  Plate. 


428 


MODERN   STEAM   PRACTICE. 


the  ring,  and  the  nut  being  placed  over  the  tube  when  in  posi- 
tion, it  is  screwed  up,  then  the  cone  is  forced  through  the  india 
rubber  and  expands  it  for  the  reception  of  the  tube ;  in  this  way 
the  ring  is  spread  out,  tightly  filling  the  recess,  and  binding  the 
tube  firmly;  the  nut  is  screwed  hard  up  on  the  tube  plate,  against 
a  washer,  or  simply  metal  to  metal,  having  a  little  red  lead  inter- 
posed. By  this  plan  the  tubes  can  be  readily  and  quickly  made 
tight,  and  the  elasticity  of  the  ring  allows  of  free  movement 
for  expansion  and  contraction.  When 
india  rubber  is  used  the  tube  ends  should 
be  tinned  to  prevent  the  deterioration 
which  takes  place  when  brass  and  india 
rubber  are  in  contact.  In  some  ar- 
rangements when  the  water  is  forced 
through  the  tubes,  their  ends  are  made 
tight  with  a  simple  flat  ring  washer  of 
india  rubber,  placed  over  the  tube 
tightly,  the  flat  end  surface  bearing  on 
the  tube  plate,  which  is  recessed  for  its 
reception,  and  in  others  wooden  plugs 
are  used,  driven  over  the  tubes,  and 
firmly  held  in  the  tube  plate,  the  expan- 
sion of  the  wood  when  wetted  making 
a  very  good  joint. 

The  arrangement  of  the  refrigerat- 
ing surface  now  falls  to  be  noticed. 
When    the   water   passes   through   the  ^','^"^ /.^'"^"^tP^^'".^-   ^' S' 

'-  "  gland  and  india-rubber  ring.    D, 

tubes  and  the  steam  all  around  them, 
we  obtain  a  larger  amount  of  surface  than  when  the  steam  is 
condensed  inside  of  the  tubes ;  but  in  the  former  case  any  incrus- 
tation that  takes  place  tends  to  choke  up  the  spaces  between 
the  tubes,  and  so  far  renders  them  useless,  as  there  is  no  pos- 
sibility of  getting  them  cleaned ;  whereas,  when  the  steam  is  con- 
densed inside  of  the  tube,  the  surface  can  be  cleansed  occasionally. 
Again,  should  any  of  the  tubes  require  repacking  at  sea,  with  the 
Avater  circulating  around  them,  the  large  covers  which  form  part  of 
the  condenser  require  to  be  taken  off,  and  should  any  leakage 
occur  through  the  joint  being  imperfectly  re-made,  air  finds  its  way 
into  the  chamber  and  impairs  the  vacuum;  whereas,  when  the 
water  passes  through  the  tubes,  with  any  leakage  occurring,  the 


Fig.  312. — Packing  Ring  for  Tubes. 

Screwed 
Cone. 


MARINE   ENGINES.  429 

water  simply  finds  its  way  into  the  ship,  and  the  working  of  the 
engines  is  not  sensibly  affected.  Looking,  however,  at  all  sides  of 
the  question,  we  may  conclude  that  the  advantages  are  in  favour  of 
inside  condensation, — provided  that  the  circulation  of  the  water  is 
properly  attended  to  and  uniformly  distributed  all  round  the 
exterior  surfaces.  When  the  surface  system  of  condensation  was 
first  introduced  into  side  lever  engines  for  the  Royal  Navy,  2800 
square  inches  of  tube  surface  was  adopted  for  the  condensation  of 
60,000  cubic  inches  of  steam  per  minute,  the  quantity  of  cold  water 
injected  being  10  gallons.  To  compare  these  quantities  with  pre- 
sent practice,  let  us  take  an  example  of  an  engine  of  400  nominal 
horse-power,  having  3170  square  inches  of  area  in  each  cylinder, 
with  a  piston  speed  of  300  feet  or  3600  inches  per  minute: 

3170  X  2  X  36oo_  380  X  2800  _      g 
60000  144 

We  thus  have  7389  square  feet  of  tube  surface,  equal  to  i8'4  square 
feet  per  nominal  horse-power.  It  will  be  observed  that  this  result 
is  about  the  same  as  that  given  for  total  heating  surface  of  boiler 
per  nominal  horse-power,  although  it  is  in  excess  of  present  prac-' 
tice,  15  to  16  square  feet  of  condensing  tubes  being  now  considered 
sufficient.  To  find  the  quantity  of  water  required  for  condensation: 
a  cylindrical  foot  of  water  equals  5  gallons,  10  gallons  will  be  con- 
tained in  3456  circular  inches,  and  as  380  times  6o,000  cubic  inches 
of  steam  passes  the  engine  per  minute,  we  have 

3600 

circular  inches  of  area  for  each  pump,  when  two  pumps  of  the 
double-action  type  are  fitted — or  a  diameter  of  say  14  inches  will  be 
enough  for  each  of  the  two  circulating  pumps.  (See  pages  508-510,) 
The  air  pumps  are  generally  made  of  the  same  capacity  as  for 
plain  injection  condensers,  and  when  one  circulating  pump  is  fitted, 
it  is  of  the  same  capacity  as  the  air  pump;  one  set  of  patterns  thus 
serves  for  both,  and  in  the  event  of  using  the  condenser  with  plain 
injection,  valves  are  so  arranged  that  the  circulating  pump  can  be 
used  for  an  air  pump.  The  circulating  pump  should  be  fitted  with 
a  valve  for  turning  on  the  bilge  water,  in  case  of  great  leakage  in 
the  ship;  a  valve  must  also  be  placed  on  the  pipe  for  shutting  off 
the  sea-water.  Should  both  of  the  pumps  be  used  as  air  pumps 
(in  cases  of  failure),  a  bilge  injection  valve  should  be  fitted.     When 


430 


MODERN    STEAM   PRACTICE. 


a  separate  centrifugal  pump  is  used,  driven  by  a  small  engine,  for 
circulating  the  water,  and  two  air  pumps  are  fitted,  the  centrifugal 
pump  should  be  arranged  to  pump  the  bilge  water  overboard,  and 
one  of  the  air  pumps  turned  into  a  circulating  pump,  the  requisite 
valves  being  placed  so  as  to  be  opened  at  the  shortest  notice.  To 
provide  against  any  accident  to  the  surface  system,  a  plain  injection 
valve  is  placed  on  the  condenser,  and  a  valve  is  also  fitted  at  some 
convenient  part  to  drain  all  the  water  out  of  the  condenser  when 
necessary. 

Various  arrangements  of  the  tubes  for  surface  condensers  are 
adopted.  For  direct-acting  horizontal  engines  of  the  return  con- 
necting-rod type,  they  are  ar- 
ranged vertically,  placed  between 
the  crosshead  guides  in  one,  or 
else  there  is  a  separate  condenser 
for  each  cylinder.  The  steam 
from  the  cylinders  enters  above 
the  top  plate,  and  being  con- 
densed falls  directly  through  the 
tubes  into  the  air  pump,  which 
is  situated  on  the  inside  of  the 
outer  frame,  and  worked  directly 

from   the  steam    piston,  while  the    Fig.  313.— Vertical  Arrangement  of  Tubes  for  Return 
,       .  •  ii  Connecting-rod  Engines. 

circulatmg    pump    occupies    the 

.  ,  A,  Tube  chamber.    B,  Air  pump,     c.  Circulating 

same    position    as    regards    the  pump. 

other    cylinder ;     the    water    is 

drawn  through  the  vessel  containing  the  tubes,  coming  in  at  the 
top,  circulating  around  the  tubes,  and  being  drawn  away,  instead 
of  forced,  by  the  circulating  pump.  The  bottom  part  of  the  con- 
denser is  generally  cast  in  two,  containing  the  guide  bars  for  the 
piston-rod  crosshead,  the  chamber  for  the  gun-metal  air  pump  or 
circulating  pump,  barrel,  valve  seats,  air  vessels,  &c.  The  flange 
for  holding  the  bottom  tube  plate  extends  the  length  and  breadth 
of  the  casting  between  the  guide  bars,  and  is  planed  all  over;  the 
bottom  tube  plate  is  fitted  on  it,  the  vessel  containing  the  tubes  is 
placed  over  it,  and  the  top  tube  plate  secured  on  the  top.  Above 
this  is  placed  the  top  part  of  the  condenser,  where  the  steam  enters; 
it  is  fitted  with  covers  on  the  top  for  getting  at  the  tubes,  the 
bottom  joints  are  reached  through  a  door  on  the  bottom  chamber 
of  sufficient  height  for  a  man  to  enter.     Some  arrangements  of  the 


MARINE   ENGINES. 


431 


vertical  type  have  a  circulating  pump  worked  directly  off  the  piston, 
with  an  arm  keyed  on  the  bottom  piston  rod  for  taking  the  air- 
pump  rod;  two  circulating  and  two  air  pumps  are  fitted,  in  other 

words  the  separate  condensers  have  each  a 
circulating  and  air  pump.     As  the  water, 
either  from  the  sea  or  from  the  condensa- 
tion of  the  steam,  gravitates  directly  into 
the  pumps,  this  arrangement  is  very  effec- 
tive, although  the  circulation  of  the  water 
is  not  so  good  as  could  be  desired — a  fault 
inherent   in   all  cases  where  the  conden- 
sation  takes    place  inside  of   the   tubes; 
Fig.  3X4.-Verticai  Arrangement     Hevertheless,  whcn  thc  watcr  passagcs  are 
suited  for  each  Cylinder  independently,  properly  arranged,  insidc  condensation  is 
A,  Tube  chamber.   B,  Air  pump.     ^^  ^^  preferred,  as  there  is  then  some  pos- 

c,  Circulatmg  pump.  -T  '  1 

sibility  of  cleaning  the  tubes  from  lubri- 
cating matter  carried  over  by  the  steam.  As  an  improvement  on 
the  vertical  arrangement,  some  engineers  have  made  the  condenser 
cylindrical,  with  a  space  in  the  centre  for  the  steam  pipe  from  the 
cylinder,  around  which  the  tubes  are  arranged  in  rings.  The  ex- 
haust steam  pipe  is  perforated  with  holes  for  distributing  the  steam 
equally;  the  condensing  surface  is  on  the  outside  of  the  tubes,  the 
water  circulating  through  them.  In  some  cases  the  condenser  is 
fitted  with  circulating  and  air  pumps  worked  directly  off  the  piston, 
in  others  the  air  pumps  work  direct,  with  a  centrifugal  circulating 
pump  driven  by  an  auxiliary  engine. 

The  horizontal  arrangement  of  tubes  next  claims  attention.  For 
direct-acting  horizontal  engines  the  tubes  are  placed  fore  and  aft 
the  ship,  arranged  in  three  divisional  parcels,  with  the  view  of 
giving  time  for  the  transit  of  the  circulating  water  which  is  being 
forced;  and  this  passes  in  the  first  instance  through  the  bottom 
row,  returning  through  the  middle  row,  and  then  passing  through 
the  third  or  top  row  before  escaping  overboard, — in  this  way  securing 
a  more  equal  distribution.  The  condenser  vessel  may  be  cast  in  one 
or  more  pieces,  with  all  the  necessary  passages,  valve  seats,  &c.,  for 
the  pumps;  the  joint  faces  for  the  tube  plates  are  all  planed,  and  the 
tube  plate  accurately  fitted.  As  the  doors  for  getting  at  the  tubes 
are  placed  at  the  ends  of  the  condenser,  both  of  the  tube  plates 
are  easily  managed,  whether  as  regards  fitting  in  the  tubes  in  the 
workshop,  or  repairing  leaky  joints  at  sea.     To  ease  the  passage  of 


432 


MODERN   STEAM   PRACTICE. 


Fig.  315. — Horizontal  Arrangement  of  Tubes  for  Return 
Connecting-rod  Engines.  A,  Tube  chamber.  B,  Air 
pump,      c.  Circulating  pump. 


the  water  through  the  tubes,  flat  air  vessels  are  cast  along  with  the 
end  doors,  by  which  the  flow  of  water  is  rendered  smoother  and 

more  equal.  The  steam  enters 
at  the  top  through  an  exhaust 
pipe  at  each  corner,  the  water 
from  condensation  falls  down 
amongst  the  tubes  and  is  car- 
ried away  by  the  air  pumps; 
one  pump  only  is  fitted  to 
engines  of  small  power,  but 
heavier  engines  have  two  air 
and  two  circulating  pumps. 

From  the  great  number  of 
such  tubes  required  to  give  the 
necessary  cooling  surface,  or  about  2  square  feet  per  indicated  horse- 
power, the  length  reaches  in  large  vessels  to  many  miles  of  tubing; 
thus  in  the  surface  condensers  for  the  new  Inman  steamer  City  of 
Ro7ne,  the  total  length  of  tubes  is  about  17  miles. 

It  appears  to  be  of  little  consequence  whether  the  water  flows  in- 
side or  outside  of  the  tubes,  so  long  as  a  good  circulation  is  kept  up. 
Sometimes  the  tubes  are  arranged  independently  for  each 
cylinder,  the  water  from  the  circulating  pump  only  passing  through 
the  tubes  twice,  instead  of  three  times.  The  pumps  are  located  on 
each  side  of  the  middle  frame,  and  are  worked  directly  off  the 
piston  of  each  cylinder.  They  are  of  large  diameter,  one  end  being 
fitted  for  the  circulating  pump,  and  the  other  end  for  the  air  pump; 
thus  for  each  function  this  arrangement  may  be  termed  a  single- 
action  double-acting  pump.  There  is  one  central  chamber  and 
pipe  for  the  suction  to  the  circulating  pumps,  which  first  discharges 
the  water  right  and  left  into  a  chamber  common  to  both,  and  then 
through  the  tubes;  the  water  returns  through  the  top  row,  and  is 
discharged  into  one  central  chamber,  with  one  pipe  overboard  for 
both  pumps.  The  arrangement  of  the  valve  seats  is  simple:  they 
are  sometimes  placed  at  the  side  of  the  pump,  sometimes  at  the  top 
and  bottom.  It  may  be  questioned  v/hether  single-acting  circulating 
pumps  are  preferable  to  smaller  sized  double-action  pumps.  Many 
engineers  are  in  favour  of  the  double-action  type,  but  consider,  so 
long  as  a  sufficient  quantity  of  condensing  water  passes  through  or 
amongst  the  tubes,  that  a  single-acting  pump,  discharging  into  a 
capacious  air  vessel,  makes  the  flow  quite  uniform  enough  for  all 


MARINE   ENGINES.  433 

practical  purposes.  The  dpors  in  the  arrangement  of  condenser 
under  notice  only  admit  of  inspecting  one  end  of  the  tubes;  for 
packing  their  central  ends  a  manhole  is  arranged  in  the  bottom 
and  top  chambers,  through  which  the  water  enters  the  tubes  at  the 
bottom,  and  from  which  it  is  discharged  overboard  at  the  top.  A 
plate  abutting  on  both  tube  plates  forms  the  division  between  the 
two.  This  arrangement  is  very  good  for  engines  of  large  power,  as 
the  tubes  are  of  a  suitable  length,  neither  too  long  nor  too  short. 

To  facilitate  the  water  from  the  condensed  steam  flowing  away 
from  the  tubes,  when  condensation  takes  place  on  their  internal 
circumference,  the  tubes  have  been  arranged  lying  at  an  angle. 
They  may  be  so  disposed  right  and  left,  or  all  in  a  cluster ;  when 
arranged  right  and  left,  the  central  chamber,  as  in  the  foregoing 
example,  becomes  the  exhaust  steam  chamber,  instead  of  the  water 
chambers.  The  air  pumps  are  arranged  on  each  side  of  the  outer 
frames  of  the  engine,  and  the  circulating  pumps  on  each  side  of  the 
central  frame;  the  suction  valves  for  both  pumps  are  inverted  and 
placed  above  the  pumps,  while  the  discharge  valves  are  arranged 
alongside,  the  circulating  water  flowing  amongst  the  tubes  at  the 
bottom  end  near  the  central  frame,  and  ejected  from  the  vessel 
containing  the  tubes  at  the  opposite  corner  at  the  top:  thus  the 
water  is  well  distributed  amongst  the  tubes — a  very  necessary  thing 
to  attend  to  in  all  arrangements. 

The  valves  for  the  pumps  are  of  the  round  disc  type,  made  of 
india  rubber,  having  grated  seatings  and  guards  of  brass.  Some  of 
these  valves  fold  up  all  round  against  a  saucer-shaped  guard  per- 
forated with  holes,  and  are  secured  to  each  hole  in  the  condenser 
by  a  cross  bar  of  iron  and  a  single  bolt.  This  bolt  passes  through 
the  centre  of  the  bar,  seating,  and  guard,  and  is  secured  with  one 
nut  at  the  top,  pressing  the  guard  and  seating  downwards,  and 
drawing  the  cross  bar  upwards  against  the  under  side  of  the  metal 
surrounding  the  hole  in  the  condenser  casting;  but  the  general  way 
is  to  secure  the  guard  and  valve  by  a  screw^ed  stud  with  a  nut  at 
the  top  to  a  large  plate  containing  all  the  gratings  for  valves,  the 
plate  being  secured  over  one  large  hole  in  the  condenser  casting  by 
gun-metal  stud  bolts  and  nuts.  Sometimes  the  guards  are  made 
quite  flat,  the  valve  moving  upwards  and  downwards  on  the  boss 
of  the  guard,  the  central  hole  in  the  india-rubber  disc  being  made 
slightly  larger,  so  that  it  moves  easily;  this  arrangement  can  be 

secured  with  a  cross  bar,  or  with  stud  bolts,  on  a  plate  common  to 

28 


434  MODERN   STEAM   PRACTICE. 

all  the  valves,  as  before  described.  The  gratings  for  these  valves 
are  formed  of  ribs  radiating  from  the  centre,  having  one  or  more 
concentric  rings,  keeping  the  area  of  each  hole  in  the  grating  equal 
to  about  I  square  inch.  The  ribs  on  the  guard  radiate  from  the 
central  boss,  and  the  ends  of  the  elongated  apertures  are  rounded 
or  left  square  as  taste  may  dictate.  Other  forms  of  valves  a.re 
oblong  shaped,  folding  up  against  a  flat  guard,  the  india  rubber 
being  secured  at  the  middle  with  stud  bolts;  the  holes  in  the 
gratings  being  made  hexagonal,  formed  around  a  circle  i  inch  in 
diameter.  This  grating  resembles  a  honeycomb,  and  may  be  said 
to  combine  the  greatest  area  with  the  least  material,  thus  obtaining 
more  free  way  for  the  passage  of  the  water — a  very  desirable  point 
to  attain  in  designing  pump  valves.  For  this  object  a  valve  seat 
has  been  designed  by  the  author  in  which  five  discs  can  be  placed 
in  about  the  same  space  as  is  usually  occupied  by  one;  the  seating 
is  in  the  form  of  a  square  box  open  at  the  bottom,  with  a  flange 
all  round  for  securing  it  to  the  condenser,  one  valve  being  placed 
on  the  top  and  one  on  each  of  the  four  sides.  This  plan  can  be 
modified  by  making  the  valve  seating  cylindrical,  the  side  valve 
being  simply  a  band  of  india  rubber,  secured  at  one  end  to  the 
cylindrical  seating,  and  a  round  disc  valve  placed  on  the  top.  The 
action  of  the  band  valve  is  one  of  expansion  and  contraction  as  it 
opens  and  shuts  with  the  reciprocating  motion  of  the  pump  piston, 
or  plunger  if  so  fitted.  It  is  scarcely  necessary  to  state  that  india- 
rubber  valves  will  work  in  any  position,  whether  lying  flat,  or  at  an 
angle,  or  even  inverted ;  the  latter  position  is  fast  finding  favour, 
where  the  passages  of  the  pump  are  so  arranged  that  the  water 
gravitates  into  the  pump  chamber  instead  of  being  sucked  or 
drawn  in. 

The  pistons  for  the  circulating  pumps  of  direct-acting  horizontal 
engines  are  packed  with  a  metallic  ring;  in  some  instances  wood 
packing  has  been  adopted,  lignum-vitae  being  preferred.  In  other 
cases  plungers  instead  of  pistons  are  used.  The  plunger  consists 
of  a  cylinder  of  brass  working  in  a  central  stuffing  box,  hemp 
packing  being  used  in  the  form  of  a  gasket.  The  cylinder  forms 
as  it  were  the  pump  barrel  and  piston,  as  in  the  double-action 
pump :  it  is  worked  directly  off"  the  steam  piston,  with  a  small  rod 
secured  to  the  cylinder  with  a  single  nut.  It  may  be  argued  that 
the  plunger  is  heavier  than  a  plain  piston,  but  it  must  be  remem- 
bered that  as"  it  is  surrounded  with  water,  it  partially  floats  as  it  were 


MARINE   ENGINES. 


435 


in  the  fluid,  consequently  the  wear  is  much  reduced ;  however,  for 
surface  condensers  it  is  not  so  compact  as  a  plain  piston.  Some- 
times the  water  chambers  at  the  ends  of  the  pumps  are  partially 
filled  up  with  a  cylindrical  casting,  formed  on  the  end  covers ;  the 
piston  rod  works  through  this  at  one  end,  and  it  is  left  plain  at  the 
other  end  of  the  pump, — that  is  to  say,  no  stuffing  box  is  required, 
but  the  cylindrical  filling-up  piece  is  simply  cast  along  with  the 
end  cover. 

Air  Pump. — The  air-pump  barrel  is  cast  in  brass,  with  fitting 

rings  at  each  end  and  at  the 
middle,  which  are  turned  to  fit 
the  parts  bored  out  in  the  con- 
denser casting;  the  barrel  is  se- 
cured by  lugs  cast  on  the  end, 
with  brass  bolts  for  firmly  bolt- 
ing it  to  the  condenser.  When 
internal  plungers  are  used,  the 
barrel  of  the  pump  forms  as  it 
were  the  central  gland,  which 
is  packed  with  hemp  in  the  usual 
manner.  All  the  bolts  and  nuts 
used  in  the  internal  fittings 
should  be  of  brass  or  Muntz 
metal ;  this  is  absolutely  neces- 
sary, for  with  wrought-iron  nuts 
oxidation  rapidly  takes  place, 
and  the  violent  motion  of  the 
water  passing  through  the  pumps 
would  wash  away  the  rust  as  it 
formed,  and  soon  render  the  bolts 
useless. 

The  pistons  are  of  the  usual 
kind,  cast  in  brass;  some  are 
merely  recessed  for  the  recep- 
tion of  a  plaited  gasket,  while  others  have  metallic  spring  rings, 
the  piston  being  fitted  with  a  junk  ring  held  down  with  bolts; 
a  gasket  is  sometimes  placed  in  the  space  between  the  brass 
packing  ring  and  the  body  of  the  piston,  thus  dispensing  with 
springs  for  keeping  the  packing  ring  up  to  the  face  of  the  barrel. 
Hydraulic    pressure    is   conveniently   employed    in    some    pumps 


Fig.  316. — Air-pump  Barrel  and  Piston. 

A,  Barrel.      B,  Piston,      c,  Rod.      D,  Junk  ring. 

E,  Packing  ring,    f,  Parallel  part  on  rod. 

G  G,  Tap  bolts. 


43^ 


MODERN   STEAM   PRACTICE. 


'////////////////////////, 


for  this  purpose.  A  small  hole  is  bored  at  each  end,  in  com- 
munication with  the  open  space  between  the  ring  and  the  piston, 
and  the  mere  forcing  of  the  water  causes  a  pressure  inside,  which 
presses  the  packing  ring  outwards  against  the  barrel  of  the  pump. 
When  one  ring  is  used,  a  small  india-rubber  ball  valve  opening 
inwards,  placed  at  both  ends,  will  tend  to  make  the  action  more 
perfect;  as  the  piston  is  going  forward  the  front  valve  would  open 
and  the  back  one  would  shut,  and  vice  versa;  thus  there  would  be 
no  escape  through  the  piston,  but  probably  this  is  not  required,  as 
a  very  small  hole  suffices,  and  the  escape  is  but  little  felt ;  and  if 
two  rings  were  fitted  in  recesses,  one  hole  suffices  at  each  end. 
Thin  spring  rings  of  brass  have  been  used  with  advantage ;  in  this 
case  the  piston  is  made  quite  solid  at  the  ends,  with  three  recesses 
turned  out  on  the  rubbing  surface  for  the  reception  of  the  rings, 
which  are  truly  turned  a 
very  little  larger  than  the 
interior  diameter  of  the 
pump;  they  are  then  sawn 
through  at  one  part,  ex- 
panded over  the  piston, 
and  sprung  into  the  re- 
cesses; in  this  way  there 
is  a  slight  spring  in  the 
rings,  which  keeps  them 
well  up  to  the  surface  of  G 
the  barrel.  Wood  packing 
with  lignum-vitse  has  been 
often  successfully  used ; 
the  piston  is  cast  as  before, 
and  the  space  for  the 
packing  is  filled  up  entirely  with  curved  blocks,  which  are  made 
to  overlap  one  another  at  the  joinings,  and  then  the  ring  is  turned 
to  the  exact  diameter  of  the  barrel,  the  body  of  the  piston  being  a 
trifle  less  in  diameter.  This  arrangement  is  what  may  be  termed  a 
solid  piston,  and  is  one  which  can  only  be  adopted  with  a  material 
that  expands  in  water;  lignum-vits  is  well  fitted  for  the  purpose. 
Solid  brass  pistons  without  any  packing  have  been  tried,  but  did 
not  succeed,  as  they  soon  failed  to  aff"ord  a  perfect  vacuum.  Hollow 
plunger  pistons  have,  however,  been  arranged,  both  internally  and 
externally.     In  the  former  plan  the  plunger  has  a  central  packing 


•'v//////////////////y////y/>/My//^y////, 

Fig.  317. — Air-pump  Plunger  and  Gland. 
A,  Plunger.     B,  Stuffing  box  and  gland,     c,  Rod. 


MARINE  ENGINES. 


437 


gland  for  forming  the  joint  between  the  two  ends  of  the  pump ;  it 
is  soHd  at  the  ends,  and  has  a  boss  at  the  centre,  bored  out  for  the 
reception  of  the  Muntz  metal  rod,  which  is  secured  by  a  screwed 
part  at  the  end  with  a  brass  nut,  drawing  up  the  plunger  against 

a  collar  formed  on  the  rod.  In 
the  latter  plan  the  plunger  is 
moved  by  a  connecting  rod 
working  directly  from  the 
cranked  shaft,  having  a  bear- 
ing inside  of  the  plunger.  For 
this  arrangement  the  bushes 
and  glands  should  be  made 
very  deep;  while  in  others, 
when  the  main  connecting  rod 
for  the  engine  works  a  plunger, 
which  in  its  turn  moves  the 
steam  piston  by  rods  attached  to  it,  it  is  advisable  to  form  the 
bottom  bush  of  the  gland  the  entire  length  of  the  stroke,  thus 
supporting  and  taking  the  thrust  of  the  connecting  rod  on  a  large 
surface.  In  this  arrangement  of  air  pump  it  is  necessary  to  reduce 
the  area  of  the  plunger,  by  having  a  hollow  guiding  trunk  at  the 
other  end,  working  through  a  suitable  packing  space  and  gland. 


Fig.  318.— Air-pump  Plunger  and  Gland. 

A,  Plunger.     B,  Stuffing  box  and  gland,     c.  End  cover. 
D,  Bearing. 


°& 


r 


m"'''^mmmf(m(m.. 


i^f''^^^MMi<.«mm^""""' 


Fig.  319. — Air-pump  Plunger  acting  as  a  guide  for  the  Crosshead  and  Piston  Rods. 
A,  Plunger.    B,  Stuffing  box  and  gland,    c,  Hollow  guide.     D,  Bearing.     E,  Rod  for  adjusting  brasses. 


All  air-pump  rods  should  be  made  of  Muntz  metal,  secured  to 
the  rod  from  the  main  piston  by  a  cotter  passing  through  a  boss 
formed  on  the  wrought-iron  rod  which  is  bored  out  for  its  reception. 
The  foo^  and  head  valves  are  formed  of  discs  of  India  rubber, 
working  on  brass  seatings.  They  are  introduced  in  all  fast-going 
engines,  to  lessen  the  disagreeable  sound  caused  by  the  metallic 
valves,  and  they  have  materially  assisted  in  bringing  the  direct- 
action  engine  to  that  high  state  of  perfection  which  it  has  now 


438 


MODERN    STEAM   PRACTICE. 


attained.  Still  further  to  dim 
rubber  discs  is  limited  by- 
means  of  a  curved  guard,  hav- 
ing a  boss  at  the  centre;  this 
boss  rests  on  the  seating,  and 
is  bored  out  for  receiving  one 
end  of  the  holding-down  bolt, 
the  other  end  passing  through 
a  cross  piece  of  wrought  iron, 
which  bears  on  the  under  side 
of  the  round  hole  over  which 
the  grating  for  the  disc  of  india 
rubber  is  placed.  The  hole 
in  the  india-rubber  disc  should 
fit  loosely  round  the  boss 
formed  on  the  guard,  and  in 
no  case  should  the  india  rubber 
be  pressed  down  on  the  seat- 
ing. These  gratings  consist 
of  annular  rings  and  ribs  ra- 
diating to  the  centre  of  the 
boss,  thus  forming  a  number  of 
oblong  holes  through  which 
the  water  passes.  The  guard 
also  requires  to  be  pierced  with 
holes,  as  the  discs  of  india 
rubber  have  a  tendency  to 
work  or  close  slowly,  were 
not  the  water  acting  on  the 
top  surface  and  pressing  it 
downwards  on  the  return 
stroke.  Some  of  these  valve 
seatings  are  secured  by  brass 
stud  bolts  and  nuts,  with 
lugs  cast  on  the  seating  for 
bolting  them  down  over  the 
holes  left  in  the  condenser 
casting,  the  joint  being  made 
with  a  ring  of  india  rubber 
recessed    into    the   seating; 


inish  the  noise,  the  lift  of  the  india- 


Fig.  320. — Single  Valve  for  Air  Pump. 

A,  Valve  seat.      b.  India-rubber  valve.      c,  Guard. 

D,  Holding-down  bolt.     E,  Cross  bar. 


O 


a^R^^ 


o^^^o 


M 


Fig.  321. — Arrangement  of  Valves  adopted  for  Air 

Pump. 
A,  Grating.      b,  India-rubber  valve.      C  c.  Guards. 
D  D,  Studs  for  guaids. 


MARINE   ENGINES. 


439 


while  the  guard  is  secured  to  the  seating  by  a  plain  bolt  and  nut. 
The  plan  now  universally  adopted  is  to  cast  a  number  of  these 
circular  gratings  in  one  large  brass  seating,  which  is  bolted  down 
over  the  oblong  holes  left  in  the  casting ;  this  brass  plate  is 
strengthened  with  bars  on  the  under  side,  and  has  a  flange  all 
round  for  the  holding-down  bolts,  which  are  screwed  in  the  casting 
as  studs  with  nuts  on  the  top ;  the  guards  are  fastened  down  to  the 
valve  gratings  by  a  stud  bolt  passing  through  each  guard,  having 
a  nut  bearing  on  the  top  of  the  guard ;  in  other  cases  the  stud  is 

formed  with  a  collar  to  screw  up 
against  in  the  grating,  which 
collar  is  somewhat  deeper  than 
the  thickness  of  the  india  rubber, 
and  the  guard  is  bolted  down  on 
the  top  of  it.  All  the  nuts  on 
these  studs  should  have  split  pins 
passing  through  the  points  of  the 
bolts,  to  prevent  the  guards  shak- 
ing loose.  In  some  arrangements 
the  valve  seats  are  all  bolted 
down  to  one  brass  seating,  having 
a  number  of  large  holes  left  in 
it  and  bored  out  for  their  recep- 
tion; and  when  the  large  plate 
is  properly  planed  on  the  surface, 
and  all  the  small  gratings  turned, 
the  joints  may  be  simply  me- 
tallic, with  a  little  thin  red  lead 
placed  between  the  surfaces 
before  they  are  bolted  down.  In 
some  instances  it  is  advisable  to 
place  a  number  of  valves  in  a 
small  space;  with  this  object  in 
view,  as  well  as  to  decrease  the 
circumferential  opening  of  the  valves,  and  yet  give  a  large  area 
for  the  passage  of  the  water,  the  valve  seating  may  be  made  in 
the  form  of  a  square  box,  open  at  the  bottom,  with  side  flanges 
all  round  for  bolting  it  to  the  condenser  casting.  With  this 
form  one  valve  can  be  placed  on  the  top  and  one  on  each  side, 
making  five  valves  in  all;  thus  with  this  arrangement,  and  the  same 


Fig.  322.  —  Box  Valve  Seat  with  sloping  sides, 
arranged  for  five  Valves  for  the  Air  Pumps. 

A,  Box  with  five  valves.    B  B,  India-rubher  valves. 
C  c,  Guards.      D,  Stud  for  guard. 


440 


MODERN   STEAM   PRACTICE. 


Fig.  323.  —  Box  Valve  Seat  with  square  sides,  arranged 
for  twelve  Valves  for  Air  Pumps. 

A,  Box  with  twelve  valves.     B,  India-rubber  valve, 
c,  Guards.     D,  Stud  for  guard. 

the   free  entrance   and  'exit  of  the 


lift  of  valve  as  in  the  former  examples,  five  times  the  area  is 
obtained;  or  with  excessively 
fast-going  engines,  the  lift  of 
valve  can  be  reduced,  a  great 
desideratum  even  with  india- 
rubber  valves,  for  undoubt- 
edly the  wear  and  tear  cannot 
be  so  great,  while  the  area 
for  the  passage  of  the  water 
is  always  greater  than  in  a 
single  valve.  In  another  ar- 
rangement four  valves  are 
placed  on  the  top  of  a  square 
box,  and  two  on  each  side, 
making  twelve  valves  in  all. 
These  sets,  and  indeed  all 
india-rubber  valve  arrange- 
ments, can  be  placed  upside 
down,  or  at  any  angle  that 
may  be  considered  best  for 
water  from  the  air  pumps.  In- 
stead of  round  valves,  some 
makers  cut  the  india  rubber 
into  oblong  flaps,  hinged  at 
the  centre  and  folding  up 
against  the  guard  on  each 
side;  by  this  means  the  holes 
for  the  bolts  do  not  weaken 
the  india  rubber  so  much  as 
when  they  are  placed  along 
the  edge.  The  holes  for  the 
passages  of  the  water  are 
hexagonal,  formed  around 
circles  i  inch  in  diameter, 
with  webs  similar  to  a  honey- 
comb. The  area  through  the 
valves  should  be  as  large  as 
possible,  and  the  grated  space 
equal  to  the  length  and 
breadth   of  the  hole   in  the 


O 


O 


E55S 


c 


Fig. 


24. — Double  Oblong  Valve  with  Hexagonal 
Grating  for  Air  Pumps. 
A,  Grating.      B,  India-rubber  valve.      C,  Guard. 
D  D,  Studs, 


MARINE  ENGINES. 


441 


condenser,  even  although  half-grated  holes  are  cut  in  the  pattern ; 
they  are  bolted  down  with  stud  bolts  and  nuts,  and  collar  bolts  at 
the  hinge  for  taking  the  flat  guard,  these  bolts  being  screwed  into 
holes  bored  and  tapped  in  cross  webs  cast  in  the  condenser  for 
supporting  the  grated  plate,  because  with  the  peculiar  form  of 
hexagonal  holes  it  is  not  convenient  to  introduce  strengthening 
ribs  in  the  grating. 

Discharp;e    Valve. — We   will    now    consider    the    arrang'ements 


Fig.  325. — Brass  Discharge  Valve  and  Box  for  Dis-         Fig.  326. — Brass  Discharge  Valve  and  Seat,  with 


charge  Pipe  from  Hot  Well,  fitted  with  Expan- 
sion Joint.  —  A,  Valve.  B,  Chest.  c,  Stuffing 
box  and  gland.  D,  Lifting  spindle.  E,  Cover. 
F,  Cotter.  G,  Hole  for  donkey  feed-valve  box. 
H,  Branch  at  side  of  ship. 


cast-iron  Valve  Chest  for  Discharge  Pipes  from 
Hot  Well.  —  A,  Valve,  e.  Chest,  c.  Lifting  eye 
and  spindle.  D,  Cover.  E,  Hole  for  cotter. 
F,  Hole  for  donkey  feed-valve  box.  G,  Branch 
at  side  of  ship. 


required  outside  of  the  condenser.  The  discharge  pipe  from  the 
hot  well  should  be  fitted  with  an  expansion  joint,  placed  on  the 
valve  chest  at  the  ship's  side;  this  valve  is  introduced  so  that  the 
sea  water  can  be  shut  off  when  the  fittings  inside  of  the  condenser 
and  air  pump  require  inspection.  The  valve  in  most  cases  is  a 
spindle  one,  with  a  long  rod  secured  to  the  top,  passing  through  a 
stuffing  box  on  the  valve-chest  cover,  and  having  a  ring  handle 
fitted  at  the  top,  for  attaching  a  block  and  tackle  for  lifting  it;  and 
as  the  valve  box  is  generally  placed  inside  of  the  coal  boxes,  means 


442 


MODERN   STEAM    PRACTICE. 


for  lifting  it  from  the  orlop  deck  should  be  provided.     In  other 

examples  the  valve  is  coned,  fitting  into  a  seat  turned  out  for  its 

reception,  the  rod  at  the  top  being  secured  by  a  nut  on  the  under  side, 

and  having  a  ring  handle  as  before ;  when  the  valve  is  lifted  up  a 

flat  key  is  driven  through  a  slotted  hole  in  the  rod,  the  key  rests  on 

the  top  of  the  gland,  and  by  this  means  the  valve  is  held  up.    Hemp 

packing  may  be  placed  in  a  recess  turned  in  the  valve  to  insure  its 

being  perfectly  water  tight.     A  variety  of  forms  of  gridiron  sluice 

valves  have  been  introduced,  each 

having  a  screwed  spindle  stepped 

at  the  bottom  of  the  valve  chest, 

and  working  in  a  nut  on  the  back 

of    the   valve,    passing    through    a 

stuffing  box  in  the  cover,  and  its 

end  fitted  with  a  handle.    Outside 

of  the  stuffing  box  a  collar  is  left 

on  the  rod,  which  is  held  down  by 

this   collar    placed   under   a   cross 

bar  fitted  to  the  cover  with  studs; 

thus  when   the   handle   is   turned 

round,   the  nut   and  valves   move 

up  or  dov/n,  opening  the  apertures 

or  shutting  off"  the  sea  water  when 

the  handle    is   turned   the   reverse 

way.     For  convenience  in  turning 

the  handle,  the  valve  chest  should 

be  placed  outside  of  the  coal  boxes, 

and  a  strong  pipe  fitted  between 

it  and  the  ship's  side.     The  valve 

chest    may   be    of  cast    iron,  but 

the  valve   and   seat  should  be  of 

brass,  and  the  top  spindle  of  Muntz 

metal.     Sometimes  large  flap  valves  are  used  on  the  side  of  the 

ship;  these  are  generally  hung  with  a  spindle  at  the  top  passing 

through  the  side  of  the  box,  and  may  be  kept  shut  with  a  weighted 

lever  on  the  end  of  the  spindle:  this  plan  has  the  advantage  of  the 

valve  opening  outwards,  and  should  the  engine  be  started  with  the 

valve  shut,  the  pressure  of  the  water  in  the  discharge  pipe  would 

open  it.     Of  course  spindle  and  conical  valves  are  likewise  placed 

so  that  the  discharged  water  forces  them  up ;  but  sluice  valves  must 


Fig.  327.  —  Conical  Brass  Valve  and  Seat,  with 
cast-iron  Valve  Box  tor  Discharge  Pipes 
from  Hot  Well. 

A,  Valve.  B,  Chest,  c,  Lifting  eye  and  spindle. 
D,  Cover.  E,  Hole  for  cotter.  F,  Hole  for  don- 
key feed-valve  box.     G,  Branch  at  side  of  ship. 


MARINE   ENGINES. 


443 


Fig.  328. — Sluice  Injection  Valve. 

Sluice  valve.      B,  Chest.      c,  Cover.      D,  Spindle. 
E,  Condenser. 


be  moved  by  hand  before  starting  the  engines,  and  in  that  respect 
they  are  not  so  safe  as  the  spindle  valves  and  other  arrangements. 
The  injection  valve  is  simply  a  sluice,  placed  in  a  suitable  valve 

chest,  which  is  bolted  to  the 
side  of  the  condenser;  the 
valve  is  of  brass,  sliding 
against  a  surface  of  the  same 
material,  let  into  the  cast- 
iron  valve  box.  The  valve 
is  provided  u^ith  a  Muntz- 
metal  spindle,  keyed  through 
a  boss  cast  on  the  back  of 
the  valve ;  at  the  top  end  of 
the  spindle  a  slotted  cross- 
head  is  fitted  for  the  lifting 
lever  to  pass  through,  and 
which  is  generally  arranged 
on  the  top  of  the  condenser. 
Gridiron  valves  are  some- 
times used,  which  are  moved  by  a  spindle  attached  to  the  valve 
with  an  eye  and  pin  passing  through  a  snug  cast  on  the  back  of 
the  valve;  with  this  arrangement  it  is  advisable  to  cast  the  valve 

chest  in  brass,  having  a 
screwed  packing  nut  at 
the  top  for  the  valve 
spindle,  with  a  corres- 
ponding screw  tapped  or 
cut  in  the  valve -chest 
cover.  For  engines  of 
small  power  plug  taps 
may  be  used,  so  arranged 
that  the  water  comes  in 
through  a  branch  on  the 
bottom  side  of  the  conical 
valve  seat,  and  passes 
through  a  hollow  plug,  the 
bottom  part  of  the  cone 
being  tapped  for  the  reception  of  a  screwed  brass  piece  which 
is  brazed  on  the  tapered  copper  injection  pipe.  The  top  part 
of  the   plug  is  fitted  with  a  packed   gland,   or  a  gland  without 


Fig.  329.- 
A,  Gridiron  valve. 


-Gridiron  Injection  Valve. 
B,  Chest,      c,  Cover.      D,  Joint  for 


lifting  arm.      E,  Condenser. 


444  MODERN    STEAM   PRACTICE. 

packing  may  be  used ;  this  is  introduced  to  keep  the  plug  in  its 
seat.  A  handle  is  keyed  on  the  plug  for  moving  by  hand,  or  levers 
are  arranged  with  rods  passing  along  to  the  starting  platform. 
The  inside  injection  pipe  is  made  of  a  conical  form,  tapering  from 
the  valve  to  the  end ;  the  apertures  are  placed  so  as  to  shower  the 
water  over  a  large  surface  in  a  way  regulated  by  the  form  of  the 
condenser.  These  apertures  are  bored  out,  or  else  cut  across  with 
a  saw;  the  former  plan  may  be  named  the  jet  system,  the  latter  the 
sheet  system,  as  the  water  then  falls  into  the  condenser  in  small 
sheets.  The  injection  pipe  is  sometimes  fitted  with  a  longitudinal 
plate  passing  up  the  centre  for  one  half  of  its  length,  by  which  the 
water  after  passing  through  the  injection  valve  is  divided  into  a  top 
and  bottom  stream,  with  holes  pierced  in  the  pipe  for  each;  but 
this  is  an  unnecessary  refinement,  for  the  injection  valve  may  be 
placed  on  the  condenser^  so  that  the 
internal  pipe  can  have  a  branch  on 
the  middle  of  its  length,  and  thus 
distribute  the  water  right  and  left. 
This  form  of  internal  pipe  should 
likewise  taper  from  the  middle  to 
each  end,  so  that  the  jets  at  the    ^  ^ 

end  may  rush  into  the  condenser  F!g.  33°.-inside  injection  Pipes. 

.   ,         ,  ,  1       r  ii  A,  Injection  pipe  tapering  toward  ends. 

With  about    as  much    force  as  those  b,  Tapering  injection  pipe. 

nearest  the  valve;  for  undoubt- 
edly were  the  pipe  made  quite  parallel,  and  pierced  with  the 
same  number  of  apertures  along  its  entire  length,  the  pressure 
of  the  water  would  decrease  at  the  extreme  ends,  owing  to  its 
escaping  into  the  condenser,  but  the  tapering  of  the  pipe  contracts 
the  water  along  its  entire  length,  and  the  pressure  from  the  head  of 
water  outside  of  the  ship  is  better  maintained,  consequently  the 
water  is  showered  over  the  condensing  area  more  equally.  It  is 
necessary  to  support  these  inside  injection  pipes,  as  the  weight  of 
water  is  considerable;  this  can  be  done  with  a  wrought-iron  support, 
fastened  to  any  of  the  ribs  inside  of  the  condenser. 

The  di/^-e  injection  valve  (Fig.  331)  is  fitted  as  low  down  in  the  con- 
denser as  may  be  deemed  necessary,  and  consists  of  a  spindle  valve 
of  brass  fitting  into  a  seat  cast  along  with  the  valve  chest,  also  of 
brass.  The  valve  has  a  spindle  on  the  top  passing  through  a  stuffing 
box  in  the  cover;  the  top  end  of  the  spindle  is  screwed,  and  works 
through  a  brass  bush  secured   in  a  cross  bar,  which  is  supported 


MARINE   ENGINES. 


445 


with  suitable  studs  let  into  the  cover.  On  the  end  of  the  spindle  a 
plain  handle  or  small  hand  wheel  is  fitted,  by  which  the  valve  is 
screwed  up  from  and  down  on  its  seat.  These 
valves  are  only  used  in  the  event  of  great  leak- 
age in  the  ship,  the  bilge  water  being  then  taken 
into  the  condenser,  and  pumped  overboard  as  in 
the  ordinary  injection  system.  In  order  to  keep 
foreign  matter  from  entering  the  condenser,  it 
is  necessary  to  protect  the  pipe  passing  from  the 
bilge  injection  valve  down  to  the  bottom  of  the 
ship  with  a  box  piece  at  the  end,  perforated  with 
a  number  of  small  holes. 

The  snifting  valve,  for  blowing  all  the  air  and 
water  out  of  the  condenser  previous  to  starting 
the  engine,  is  placed  at  the  lowest  part  of  the 
condenser,  on  which  a  branch  is  cast  for  holding 
it.  It  is  a  spindle  valve  opening  upwards,  and  is 
Fig.  331. —  Bilge  Injection  fitted  with  a  baffle  plate  placed  on  the  valve  box, 

Valve. — A,   Spindle    and  1         1   •    1  1  1  1        •  j 

valve.  B,chest.  c.Cover.  through  which  a  thumb  screw  works  m  a  screwed 
D,  crosshead.    ^ E  Col- ^^.^^^   \iv^^\i-   by  thls   mcans  the  valve   is   held 

umns.      F,  Hand  wheel.  '         J 

down   after  the  process  of  blowing  through  is 
completed,  and  indeed,  when   the  vacuum  is  formed  in  the  con- 
denser, the  atmospheric  pressure  comes  instantly  into   operation, 
firmly  closing  the  valve,  which   can   then    be 
secured  by  the  thumb  screw  at  leisure. 

The  feed  pump  is  generally  of  the  single-act- 
ing plunger  type ;  the  body  of  the  pump  is  of 
cast  iron,  with  a  brass  gland  and  bush  at  the 
bottom  of  the  stuffing  box ;  when  bolted  to  the 
side  of  the  condenser  casting,  the  brass  plunger 
is  worked  from  an  arm  keyed  on  the  piston 
rod,  and  has  an  inside  rod  of  iron,  by  which 
the  plunger  can  be  disconnected  while  the 
engine  is  in  motion.  The  disconnecting  gear 
consists  of  a  thumb  screw  pressing  against  a 
brass  block  let  into  the  end  of  the  pump  ram, 
the  inside  rod  being  of  sufficient  length  to 
work  loosely  in  the  hollow  ram  when  the  plunger  is  at  the  bottom 
of  the  stroke.  When  connecting  the  pump,  the  thumb  screw  should 
press  lightly  on  the  brass  block  until  the  plunger  is  pressed  up 


Fig.  332. — Snifting  Valve. 

A,  Valve.     B,  Chest,     c,  Cover, 
D,  Set  screw. 


446 


MODERN   STEAM   PRACTICE. 


against  a  collar  left  on  the  rod  (this  must  take  place  in  the  act  of 
forcing  the  water),  the  ram  is  drawn  outwards,  and  in  the  return 
stroke  it  slips  or  slides  on  the  bush  piece,  until  it  is  stopped  with 
a  collar  on  the  rod,  then  the  thumb  screw 
can  be  tightened  up.  This  simple  contrivance 
is  far  superior  to  any  other  for  disconnecting  the 
plungers  when  the  engine  is  in  motion.  Some 
makers  prefer  placing  these  pumps  at  the  back 
of  the  condenser,  fitting  them  to  the  platform 
on  which  the  gearing  is  located  for  handling 
the  engine,  either  above  or  below  the  centre  line 
of  motion  of  the  piston  and  adjuncts;  with  the 
former  arrangement  the  plunger  js  connected 
to  a  stud  placed  on  the  top  of  the  crosshead 
arm  for  taking  the  piston  rods,  and  in  some 
cases  is  worked  directly  from  a  prolongation  of 
the  air-pump  rod,  which  passes  through  a  stuff- 
ing box  at  the  back  of  the  air-pump  cover. 
Piston  pumps  are  sometimes  used  with  ad- 
vantage, the  brass  cylinder  in  which  the  solid 
or  packed  piston  works  being  let  into  a  part 
of  the  condenser  casting,  and  generally  worked 
directly  off  the  steam  piston,  in  the  same 
manner  as  the  air-pump  piston;  with  this  ar- 
rangement the  pump  is  double  acting,  one  end 
being  used  for  the  feed  and  the  other  for  the 
bilge  pump.  The  latter,  in  other  arrangements, 
is  exactly  similar  to  the  feed-pump  barrel,  and 
is  placed  on  the  condenser  on  the  opposite 
side  of  the  centre  line  of  crosshead  from  that 
of  the  feed  pump,  and  can  be  worked  off  an 
arm  keyed  on  the  piston  rod;  or  when  it  is 
fitted  to  the  starting  platform  at  the  back  of  pj^  333  _p^,d and  Biige Pump. 
the  condensers,  it  is  connected  to  the  bottom  a,  Pump,  b,  Ram.  c,  inside 
arm  of  the  crosshead  in  a  similar  way  to  that 
of  the  feed  pump.  Many  prefer  the  pump  ar- 
rangements fitted  to  the  condenser,  as  the  labour  of  fitting  up 
is  thereby  greatly  reduced,  and  the  engine  as  a  whole  rendered 
more  compact. 

The  valve  box  for  the  feed  pump  is  of  brass,  and  is  generally 


rod.      D,  Thumb  screw. 
E,  Stuffing  box  and  gland. 


MARINE   ENGINES. 


447 


placed  at  the  end  of  the  pump;  the  feed  or  delivery  and  the  relief 
valves  are  placed  on  the  same  level,  while  the  suction  valve  is 

immediately  under  the  relief  valve,  which 
is  fitted  with  a  spiral  spring  compressed 
by  a  set  screw  working  in  the  top  of  a  brass 
bow  placed  over  the  spring;  the  pressure 
on  the  valve  should  be  a  little  in  excess  of 
the  steam  pressure  in  the  boiler.  The  sole 
use  of  this  valve  is  to  allow  the  water  in 
the  pump  to  escape  into  the  hot  well  when 
the  feed  regulating  valve  on  the  boiler  is 
shut;  a  branch  is  cast  on  the  relief- valve 
box,  with  a  pipe  leading  into  the  chamber 
above  the  head  valves,  by  which  the  water 
when  not  required  in  the  boiler  is  returned 
and  finds  its  way  overboard.  A  plug  valve 
for  shutting  off  the  suction  is  also  fitted  to 
the  valve  box;  this  is  used  for  shutting  off 
the  water  in  the  event  of  any  of  the  pump  valves  requiring  inspec- 
tion, and  may  be  used  for  stopping  the  supply  to  the  pumps,  in 


Fig.  334. — Valve  Box  for  Feed  Pump. 

A,  Valve  box.    B,  Suction  valve. 

C,  Delivery  valve.    D,  Relief  valve. 

E,  Spring.    F,  Bow.  G,  Set  screw. 


Fig.  333. — Valve  Box  for  Feed  Pump. 

A,  Valve  box.      B,  Suction  valve,      c,  Delivery  valve,      d.  Relief  valve.      E,  Spring. 
F,  Bow.      G,  Set  screw. 


which  case  the  plungers  may  be  kept  working,  although  no  water 
can  be  forced  into  the  boiler  or  through  the  relief  valve.     India- 


448 


MODERN   STEAM   PRACTICE. 


rubber  valves  are  sometimes  used  for  the  feed  pump,  having 
conical  brass  seats  grated  in  the  casting,  and  let  into  a  cast-iron 
valve  box  containing  the  suction,  discharge,  and  relief  valves, 
the  latter  being  a  brass  valve  fitted  with  a  spring  in  the  usual 
maimer.  All  the  valves  may  be  placed  on  the  same  level;  the 
suction  at  one  end  of  the  valve  box,  the  discharge  in  the  middle, 
and  the  escape  at  the  other  end,  with  a  passage  leading  underneath 
the  discharge  and  escape  valves  from  the  top  of  the  suction  valve, 
and  a  lower  return  passage  from  above  the  escape  in  connection 
with  the  suction  pipe  or  hot  well.  In  some  instances  suction  and 
discharge  valves  only  are  fitted,  with  a  separate  relief  valve  placed 
on  some  other  part  of  the  feed  pipe.  A  similar  arrangement  of 
valves  is  required  for  the  bilge  pump,  but  of  course  a  relief  valve  is 
not  needed,  as  the  bilge  water  is  pumped  directly 
overboard,  and  a  non-return  valve  placed  on  the 
ship's  side.  The  india-rubber  valves  are  used 
to  prevent  the  disagreeable  noise  caused  by 
brass  valves  beating  sixty  or  more  times  in 
the  minute.  To  obviate  this  evil  wooden  rings 
have  been  recessed  into  the  valve  with  advan- 
tage. Perhaps  the  best  plan  of  doing  this  would 
be  the  Cornish  one  of  recessing  the  wood  into 
the  valve  seating,  in  the  same  way  as  for  large 
double-beat  valves  for  the  pumps  in  deep  mines. 
The  valves  in  this  case  would  be  discs  turned  Fig.  336.— Vaive  Box  for  Biige 
on  the  face,  with  central  holes  for  working  on  "'"^"    . 

.      A,  Valve  box.    B,  Suction  valve. 

spindles;  thus  the  valves  are  guided  by  this  c, Delivery vaWe.  d, Guard 
means,  necessitating  a  central  boss  with  wood-  E.'cuard'^F.'^SeTscTew!^^^' 
bearing  surface.  Of  course  the  valves  can  be 
of  the  spindle  type,  working  through  and  guided  by  holes  bored 
in  the  bosses  cast  along  with  the  valve  seats.  An  air  vessel 
should  be  placed  on  the  feed-pump  valve  box,  or  on  some 
part  of  the  feed  pipe  between  the  boiler  and  the  top  of  the  dis- 
charge valve,  by  which  any  sudden  strain  caused  by  the  passage 
of  the  water  through  the  pipes  is  greatly  neutralized,  and  the 
discharge  into  the  boiler  is  rendered  more  equal. 

The  hand  pump  (Fig.  337)  is  an  additional  one,  which  can  be  worked 
either  by  hand,  or  if  required  connected  to  the  engine.  Its  duty  is 
somewhat  complicated,  as  it  must  be  fitted  to.  draw  water  from  the 
boiler,  from  the  bilge,  and  from  the  sea;  while  the  discharge  pipes 


MARINE   ENGINES. 


449 


must  be  arranged  to  pump  water  into  the  boilers,  on  deck,  and  over- 
board. The  most  convenient  form  for  this  pump  is  the  plunger  type. 
It  is  generally  placed  vertically  at  the  end  of  the  cranked  shaft,  the 
body  of  the  pump  being  bolted  down  to  the  engine  keelson ;  some- 
times it  is  placed  horizontally,  and  is  fitted  to  the  condenser,  fitting 
strips  and  joggles  being  cast  on  the  parts  for  its  reception.  The 
trunk  plunger  is  actuated  by  a  pin  and  rod ;  the  pin  is  fitted  to  the 

end  of  the  cranked  shaft,  and  has  a 
rod  with  a  plain  brass  bush,  working  in 
a  hollow  plunger  rod  attached  to  a  pin 
passing  through  a  joint  at  the  bottom 
of  the  plunger;  this  hollow  rod  has  a 
thumb  screw  and  brass  block  at  the  top 
for  throwing  into  gear  or  disengaging 
the  pump.  When  working  free,  the 
inside  rod  merely  moves  up  and  down 
in  the  hollow  brass  piece,  which  vibrates 
along  with  the  rod  as  the  crank  pin 
revolves;  when  the  pump  is  required, 
with  the  engine  in  motion,  a  cotter  is 
driven  through  a  slot  in  the  brass  rod, 
and  forms  the  stop  for  the  inside  rod 
butting  against,  which  it  does  gently 
by  means  of  the  thumb  screw  and  fric- 
tion block,  as  with  the  feed  pumps ;  the 
thumb  screw  is  then  tightened  up  and 
the  connection  is  complete.  For  work- 
ing the  pump  by  hand,  a  bracket  is 
cast  along  with  the  body  of  the  pump, 
^   ^    ,       ,  on  which  a  lever  is  fitted,  and  flat  side 

A,  Pump.     B,  Plunger,    c,  Stuffing  box  and 

gland.   D,  Hand  lever  with  side  connect- rods   are  counccted  to   the  piu  at  the 

ing  rods.      E,  Stud.      F,  Snug  for  stud.    i       .  ,  r   ^i  i  i   m        ,i         i 

cHolIowrod.    H, Thumb  screw.    ., Con-  bottom   of   the    pluUgCr,  whllc    thc    IcVCr 

necting  rod.     K,  Crank  pin  on  the  end  ^as  a  part  forgcd  along  with  it  for  the 

of  shaft  r  t>  t> 

reception  of  a  long  handle.  When  the 
inside  rod  is  disengaged,  and  when  the  engine  is  not  going,  or  even 
were  it  in  motion,  the  pump  can  be  thus  worked  by  hand,  the  hollow 
brass  rod  merely  sliding  on  the  wrought-iron  one  inside.  Of  course 
when  the  pump  is  worked  by  the  engine,  the  hand  lever  and  con- 
nection vibrate  with  the  motion,  it  is  therefore  imperative  that  the 
handle  should  be  disengaged  from  the  pump  lever,  a  socket  being 

29 


Fig.  337. — Hand  Pump. 


450 


MODERN   STEAM   PRACTICE. 


forged  on  it  for  that  purpose.  The  pin  on  the  end  of  the  cranked 
shaft  is  forged  on  a  flat  ring,  which  is  accurately  turned,  and  bolted 
to  the  end  of  the  main  shaft,  a  projection  being  left  on  the  shaft  for 
its  reception.  Some  makers  connect  the  pump  by  means  of  a  plain 
rod,  having  a  sliding  block  fitted  with  a  pin,  working  in  a  guide 
formed  on  the  disc  that  is  bolted  to  the  end  of  the  cranked  shaft ; 
this  block  and  pin  is  moved  by  a  screw  and  thumb  handle,  by 
which  means  the  stroke  can  be  varied  to  any  extent  within  the  full 
throw,  and  even  brought  to  the  centre  of  the  shaft,  thus  imparting 
no  motion  whatever  to  the  pump  ram.  This  is  certainly  a  very 
simple  means  for  disconnecting  the  pump,  but  at  the  same  time  no 
provision  is  made  for  working  it  by  hand, 
which  is  the  chief  thing  to  be  studied  in  these 
pump  arrangements. 

The  valves  are  generally  metallic,  or  india- 
rubber  discs  may  be  used,  and  at  the  bottom 
of  the  pump  an  escape  valve  is  fitted  loaded 
with  a  lead  weight.  This  latter  valve  is  re- 
quired, as  there  are  many  valves  on  the  delivery 
pipe  which  may  be  shut  when  the  engine  is 
started,  or  even  close  when  it  is  in  motion,  due 
notice  of  which  will  be  given  by  the  water  being 
ejected  through  the  escape  valve.  The  end  of 
the  suction  pipe  passing  down  to  the  bilges 
must  have  a  box  perforated  with  small  holes  to 
prevent  foreign  matter  entering  the  pump. 

^,.  ,  -r^.  1  j_    -I  Fig.  338.— Kingston  Valve, 

Kmo-stoii  valves. — Kmgston  valves  must  be 

&•  <=>  A,  Spindle  and  valve.     B,  Chest. 

fitted  to  the  pipes  for  injection,  feed,  and  blow-    c.stuffingbox.  dd, Columns. 

-^  ^  ,        ,       .,  .  o  J'JJ       E,  Crosshead.    F,  Hand  vifheeL 

off  for  the  boiler,  steam  pump,  &c.,  and  indeed  ^^  Thumbscrew,  h, Grating, 
to  all  pipes  passing  through  the  bottom  of  the 

ship.  The  arrangement  here  is  similar  to  that  for  the  oscillating 
engine  already  described ;  strong  cast-iron  branches  being  placed  at 
the  ship's  side  for  preventing  the  rapid  deterioration  of  the  wrought- 
iron  plates  by  the  galvanic  action  of  the  two  metals — brass  and 
wrought  iron — in  juxtaposition,  assisted  greatly  by  the  adjoining 
copper  pipes.  In  preference  to  the  Kingston,  some  use  spindle 
valves,  fitted  with  a  ^crew  on  the  spindle  working  into  a  nut  in  the 
cross  piece,  having  a  jam  thumb  screw  fitted  on  the  top  of  the 
crosshead. 

The  various  arrangements  of  hand  wheels  for  starting,  reversing, 


MARINE  ENGINES. 


451 


and  stopping  the  engines  are  given  in  another  part  of  this  Work  (see 
page  no). 

The  usual  hand  gear  for  the  blow- through,  injection,  throttle 
valve,  blow-off  valve  from  cylinder,  and  all  the  other  necessary- 
handles,  should  be  arranged  on  the  same  platform.  We  prefer  this 
platform  to  be  on  the  same  level  as  the  engine-room  floor  plates, 
but  some  engineers  place  it  on  the  top  of  the  condenser;  and  cer- 
tainly in  this  position  the  engineer  commands  a  better  view  of  the 
machinery,  but  his  duties  when  the  ship  is  under  steam  lying 
between  the  engine  and  the  boiler  rooms,  the  hand  gear  should  be 
placed  in  such  a  position  that  it  can  be  reached  at  a  moment's 
notice,  and  as  near  the  main  starting  wheel  governing  the  link 
motion  for  actuating  the  steam  valves  as  convenient.  The  blow- 
through,  injection,  and  throttle  valve  handles  should  be  placed  in  a 


Fig.  339- — Hand  Gear. 

A,  Injection  handle  and  lever.     B,  Blow-through  handle  and  lever,     c,  Throttle  handle  and  lever, 
D,  Sectors.     E  E,  Thumb  screws. 

row.  Some  arrangements  have  a  central  rod  for  the  injection  valve, 
a  hollow  tube  with  levers  for  the  blow-through  placed  over  it,  and 
another  over  this  for  the  throttle.  When  thus  arranged  the  rods 
cannot  be  connected  directly  to  the  various  valves,  but  the  line  of 
motion  can  be  conveniently  changed  by  small  sector  wheels  cast  in 
brass,  and  bevelled  to  suit  the  requirements ;  in  other  cases  short 
levers  are  keyed  on  the  ends  of  the  inside  rod  and  to  the  outside 
tubes,  and  fitted  with  pins  and  rods  for  changing  the  direction  of 
the  motion. 

Having  considered  the  main  details  necessary  in  the  manufacture 
of  the  direct-action  horizontal  marine  engine,  we  will  now  notice 
the  means  to  be  adopted  for  effecting  a  thorough  lubrication  of  all 
the  moving  parts  in  the  machinery.     The  main  bearings  are  those 


452  MODERN   STEAM   PRACTICE. 

most  important,  and  their  friction  can  always  be  reduced  to  the 
minimum  by  giving  them  ample  rubbing  surface, — this,  combined 
with  good  material  and  first-class  workmanship,  being  essential  in 
all  engines,  more  especially  in  those  of  great  power,  encountering 
permanent  loads,  and  working  at  a  high  velocity.  Lubricators 
should  not  be  too  elaborate  in  design;  in  their  construction  plain- 
ness and  efficiency  should  rather  be  aimed  at  The  oil  cups  placed 
on  the  main  bearings  are  cast  in  brass,  with  covers  and  oil  pipes  for 
siphon  wicks;  they  should  be  divided  into  two  compartments,  one 
for  the  oil  and  another  having  a  plain  hole  bored  down  through  the 
brasses,  for  water  lubrication  in  the  event  of  the  bearings  becoming 
hot.  To  effect  this  properly  a  pipe  is  carried  across  the  engine 
directly  over  the  main  bearings,  and  supported  with  standards  of 
wrought  iron  secured  to  the  main  framing.  This  pipe  is  provided 
with  plug  taps  and  water  distributors  for  each  main  bearing  and 
crank  pin;  it  also  carries  oil  cups  with  long  siphon  pipes  for 
lubricating  the  crank  pins,  the  wick  hanging  down  a  very  little 
past  the  end  of  the  pipe.  The  water  enters  from  the  sea  directly, 
a  branch  pipe  being  cast  on  one  of  the  Kingston  valves,  and  an 
ample  flow  is  obtained  for  showering  over  the  bearings  in  the  case 
of  violent  heating.  Sometimes  the  standards  for  carrying  the  water 
pipe  placed  over  the  main  bearings  are  hollow  pipes  jointed  on  the 
top  of  the  framing,  and  provided  with  a  valve  at  the  bottom,  one 
pipe  standard  being  placed  on  each  frame;  thus  each  bearing  can 
be  supplied  with  water  independently.  The  pipe  at  the  top  has 
coupling  joints  with  nuts,  or  simple  flange  joints  may  be  adopted; 
on  the  standard  pipe  nearest  the  Kingston  valve  a  branch  is  cast, 
for  connecting  the  supply  pipe  to  the  Kingston,  and  a  plug  tap  is 
generally  fitted  to  one  of  the  standards,  with  means  of  attaching  a 
flexible  pipe  to  it,  for  showering  water  over  any  other  part  of  the 
engine.  The  connecting  rods  have  cups  fitted  on,  with  covers 
having  raised  pipes  and  tongue  pieces,  for  licking  off  the  oil  from 
the  siphon  wicks  suspended  from  the  oil  cup  fitted  overhead;  by 
this  means  the  crank  pin  is  thoroughly  supplied  at  each  revolution 
of  the  cranked  shaft.  All  the  other  lubricators  for  the  engine  con- 
sist of  cups  cast  in  brass,  fitted  with  inside  pipes  and  siphon  wicks, 
and  fastened  to  the  various  parts  in  such  a  way  that  they  can  be 
removed  when  they  require  to  be  cleaned.  Many  journal  bearings 
have  cups  cast  on,  and  plain  holes  bored  through;  this  plan  is 
preferable  to  that  of  merely  boring  a  countersunk  hole  in  the  journal 


MARINE   ENGINES. 


453 


brackets,  into  which  the  oil  cannot  be  poured  steadily,  and  generally 
runs  over  on  the  machinery,  whereas  in  the  former  plan  the  oil  is 
poured  into  the  small  oil  cup  and  is  beneficially  used.  The  tallow 
cups  for  lubricating  the  slide  valve,  cylinder,  and  pistons  are  similar 
to  those  in  general  use,  which  have  been  already  explained  in 
treating  of  the  oscillating  engine. 

Ttwning  gear. — When  the  vessel  is  in  port,  with  the  steam  down, 
it  is  necessary  to  turn  the  engines  daily  by  hand,  so  as  to  change 

the  relative  position  of  the  work- 
ing parts,  and  prevent  the  fur- 
rowing induced  by  the  galvanic 

action  resulting  from  the  contact 

—J  of  the  wrought-iron  piston  rods 
and  brass  glands,  as  well  as  to 
facilitate  the  adjustment  of  the 
slide  valves  or  any  other  part  of 
the  machinery.  The  arrange- 
ment for  doing  so  consists  of  a 
worm  working  into  a  wheel  fitted 
to  the  end  of  the  cranked  shaft, 
which  has  a  cast-iron  coupling 
for  bolting  it  to  the  boss  or  coup- 
ling cast  on  the  wheel ;  the  worm 
wheel  being  thrown  in  and  out 
with  suitable  mechanism.  Some 
makers  simply  key  up  the  worm- 
shaft  bearings,  which  work  in 
blocks  fitted  to  a  cast-iron  guide 
plate,  arranged  across  the  line  of 
the  lying  shafting;  others  place 
the  worm  wheel  vertically  at  the 
side  of  the  turning  wheel,  and 
draw  out  the  bottom  bush  on 
which  the  worm  shaft  is  stepped, 
by  means  of  a  small  hand  screw 
and  wheel  working  through  a  brass  bush  cast  on  the  plate  the 
bush  rests  on,  the  top  part  of  the  shaft  being  supported  by  a 
bracket  bolted  to  some  part  of  the  engine-room  bulkhead.  Some 
engineers  adopt  an  eccentric  motion  similar  to  the  back  motion  of 
a  turning  lathe,  as  a  means  of  putting  the  worm  wheel  in  and  out 


Fig.  340. — Turning  Gear. 

A,  Worm  wlieel.  B,  Worm  pinion,  c  c,  Eccentrics. 
D,  Handle  connecting  the  eccentric  arms.  E,  Plate 
for  bolting  to  the  bulkhead. 


454 


MODERN    STEAM   PRACTICE. 


of  gear,  A  square  part  is  formed  on  the  end  of  the  worm-wheel 
shaft,  to  receive  a  ratchet  brace  lever,  fitted  with  a  double  paul  to 
work  either  way,  and  a  part  is  left  on  the  lever  to  receive  the 
socket  formed  on  the  long  hand  lever,  on  the  end  of  which  is  forged 
an  eye  for  securing  a  rope,  which  can  be  taken  to  any  part,  so  that 
a  number  of  hands  can  be  employed  in  turning  the  engine — a 
needful  provision  as  the  back  of  the  engine  space  is  generally 
confined. 

BOILER   FITTINGS. 

Safety  valve. — Amongst  the  boiler  fittings  the  most  important 
is  the  safety  valve.  In  river  steamers  there  are  generally  two  valves 
fitted  to  each  boiler,  placed 

0 


Q 


in  one  valve  chest,  with  the 
waste-steam  pipe  between 
them.  The  valves  and 
seatings  are  of  brass;  a 
spindle  of  wrought  iron  is 
fitted  to  the  top  of  the 
valve,  passing  through  a 
cover  on  the  valve  chest, 
and  is  fitted  with  an  eye 
on  the  outside.  This  eye 
is  arranged  so  as  to  turn 
round  the  valve  with  a 
hand  bar,  to  prevent  it 
becoming  fast  on  its  seat. 
The  valve  is  loaded  with 
a  certain  weight  placed  in 
the  valve  chest  above  the 
valve;  and  on  the  outside 

of  the  casing  flat  discs  of  cast  iron  are  placed  on  the  spindle,  or 
taken  off,  as  the  steam  is  raised  above  the  usual  working  pressure, 
or  is  blown  off  by  the  waste  pipe.  The  waste-steam  pipe  is  of 
copper,  fitted  with  a  gland  and  stuffing  box,  cast  on  the  valve  chest ; 
and  there  is  a  small  branch  at  the  bottom  of  the  chest  for  running 
off  the  water  accumulating  from  the  condensation  of  the  waste 
steam.  This  water  is  generally  collected  in  a  tank  fitted  to  the 
side  of  the  vessel,  and  is  used  for  cooking  purposes,  being  an  all- 
important  fresh-water  supply  for  ocean  steam  ships. 


Fig.  341.— Safety  Valve. 
A,  Valve  and  spindle.      b.  Chest.      C,  Weights. 


handle.     E,  Waste-steam  pipe, 
condensed  steam.      G,  Boiler. 


D,  Turning 
F,  Hole  for  running  ofi  the 


MARINE   ENGINES. 


455 


The  safety  valves  for  such  ships  differ  materially  from  those  of 
river  steamers,  inasmuch  as  the  weights  are  placed  entirely  in  the 
valve  chest  above  the  valves,  or  else  inside  of  the  boiler;  the  latter 
method  requiring  a  long  spindle  and  socket  connected  to  the  valve 
spindle.  In  the  former  method  the  valve-chest  covers  are  under 
lock  and  key,  and  in  the  latter  the  weights  cannot  be  got  at;  the 
valves  cannot  therefore  be  tampered  with,  or  the  boilers  subjected 
to  undue  pressure.  Two  safety  valves  are  fitted  to  each  boiler, 
placed  in  one  valve  chest,  with  a  branch  cast  on  for  the  horizontal 
copper  pipes  passing  along   to  the  branch  pipe  for  the  vertical 

waste- steam  funnel;  this 
branch  is  fitted  with  a  stuff- 
ing box  and  gland,  to  allow 
for  the  expansion  of  the 
copper  pipes.  The  main 
waste-steam  pipe  is  fitted  to 
a  flange  on  the  top  of  the 
central  branch  box,  which  is 
made  of  cast  iron,  having  a 
small  branch  at  the  bottom 
for  running  off  the  water  de- 
rived from  the  condensation 
of  the  waste  steam  in  the 
act  of  blowing  off  from 
undue  pressure  or  otherwise. 
The  valves  are  lifted  by  a 
lever  arrangement,  having  a 
spindle  within  the  valve 
chest;  this  lever  is  carried 
along  to  any  convenient 
position,  and  supported  by 
a  bracket  at  the  end,  which 
is  bolted  to  the  top  of  the  boiler;  a  long  lever  handle  or  other 
arrangement  is  fitted  at  the  end  of  the  shaft,  with  a  quadrant  fitted 
to  the  boiler,' and  drilled  with  a  number  of  holes;  a  small  pin  is 
provided,  connected  to  a  fine  chain  to  prevent  it  being  lost.  By 
this  means  the  valves  can  be  raised  their  full  lift,  or  only  a  very 
small  part,  as  may  be  desired,  and  held  in  position  by  passing  the 
pin  through  the  quadrant  and  lever  handle.  When  the  weights 
are  inside  of  the  boiler,  the  spindle  for  supporting  them  has  a  pin 


Fig.  342. — Safety  Valve. 

A,  Valve.      B,  Chest.      c.  Weights, 
lifting  arm.      E,  Lifting  arm. 


D,  Slot  rod  for 
r,  Guide. 


45^  MODERN   STEAM   PRACTICE. 

joint  connected  to  a  collar  brass  connecting  piece,  which  is  cottered 
to  the  valve  spindle,  the  forked  lifting  arms  of  wrought  iron  work 
loosely  on  the  collar,  and  the  shaft  is  bracketed  at  the  one  end  from 
the  crown  of  the  boiler,  and  at  the  other  end  it  passes  through  a 
stuffing  box  with  gland,  fitted  to  the  front  plate  of  the  boiler;  the 
shaft  being  fitted  with  a  lever  handle  and  quadrant,  or  any  other 
suitable  appliance,  such  as  a  worm  wheel  and  toothed  quadrant  on 
the  shaft,  with  a  turning  handle  and  bracket  fitted  to  the  worm 
spindle. 

In  all  arrangements  for  lifting  the  valves  it  is  imperative  that 
their  free  action  should  not  be  interfered  with;  at  any  position  of 
the  lifting  levers,  the  valves  when  acted  on  by  the  steam  pressure 
must  lift  solely  by  that  pressure,  as  the  lever  handles  are  only 
arranged  to  lift  the  valves  in  the  act  of  blowing  out  the  boilers  or 
easing  them  when  the  engine  is  not  at  work.  It  is  also  essential 
that  all  the  rubbing  parts  should  be  bushed  with  brass  to  prevent 
corrosion :  this  is  a  most  important  point,  for  where  the  free  action 
of  the  levers  and  shaft  is  not  perfect,  accidents  may  occur,  which 
due  attention  to  their  fittings  will  alone  prevent.  In  order  that 
the  surfaces  of  the  valves  may  be  changed  occasionally,  the  covers 
are  fitted  with  hollow  guides  for  the  ends  of  the  spindles, — that  is, 
when  the  weights  are  contained  in  the  valve  chests;  the  chests  are 
removed,  when  the  spindle  can  be  gripped  and  the  weights  and 
valves  turned  slightly  round.  When  the  weights  are  placed  inside 
of  the  boiler,  the  valve-casing  covers  can  be  removed,  and  the 
valves  turned  with  a  key  or  spanner,  by  means  of  a  projecting 
square  piece  cast  on  the  top  of  each  valve.  Many  arrangements 
do  not  allow  of  this  being  done, — for  instance,  when  the  lifting  arms 
work  in  slotted  connections,  as  is  sometimes  the  case  when  the 
weights  are  inside  of  the  boiler;  but  all  lifting  arms  should  be 
forked,  lifting  the  valves  and  weight  by  working  on  a  collar  formed 
on  the  weight  spindle.  For  inside-weighted  valves  the  spindle  must 
be  guided  at  the  bottom  through  brass  bushes  on  the  spindle  and 
guiding  piece  fitted  to  the  boiler.     (See  page  462.) 

The  steam  stop  valve  is  simply  a  spindle  one,  generally  lying  on 
its  side,  fitted  with  a  brass  seating,  placed  in  a  cast-iron  valve  chest, 
having  a  branch  cast  on  above  the  valve  for  the  pipe  connections. 
Where  two  valves  are  used,  one  of  these  branches  has  a  plain  flange, 
and  the  branch  on  the  other  valve  chest  is  fitted  with  an  expansion 
joint.     On  the  top  of  the  valve  is  cast  a  part  for  taking  the  head  of 


MARINE   ENGINES. 


457 


the  lifting  spindle,  in  which  it  can  freely  revolve;  the  spindle  passes 
through  a  stuffing  box  on  the  casing  cover,  with  a  gland  for  pressing  • 
down  the  packing;  between  the  valve  and  the  bottom  part  of  the 
stuffing  box  a  screwed  part  is  turned  on  the  spindle,  working  in  a 
brass  nut  let  into  the  bottom  part  of  the  stuffing  box.  A  handle 
is  fitted  to  the  spindle,  and  when  it  can  be  conveniently  reached  is 
quite  close  to  the  gland ;  but  when  the  valve  box  is  placed  beyond 
reach  of  the  attendant,  the  spindle  is  prolonged  by  a  wrought-iron 
connecting  piece,  fitted  with  a  socket  for  taking  the  brass  valve 
spindle,  and  a  wrought-iron  bracket  is  fitted  to  the  casing  cover. 
The  valve  chest  in  those  instances  is  placed  vertically  and  inverted, 

so  as  to  be  worked  from  the 
boiler-room  floor  plates,  which 
is  decidedly  the  most  convenient 
position  for  turning  round  the 
handle  for  opening  and  shutting 
the  valve.  A  small  branch  is 
generally  cast  on  one  of  the  stop- 
valve  chests  between  the  boiler 
and  the  valve,  for  fitting  the  small 
stop  valve  in  connection  with  the 
auxiliary  steam  pump,  by  this 
means  saving  an  extra  hole  in 
the  boiler  plates.  Of  course  the 
position  of  the  steam  pump  must 
be  fixed  in  the  engine  room,  and 
the  branch  cast  on  the  stop  valve 
nearest  to  it,  thus  effecting  a 
saving  in  piping,  which  would 
not  be  the  case  if,  for  instance, 
the  steam  pump  was  arranged  on  the  starboard,  while  the  small 
stop  valve  was  fitted  to  the  larboard  main  stop  valve,  as  the  case 
may  be.  The  stop  valve  for  the  auxiliary  steam  pump  should  in 
no  instance  be  fitted  to  the  steam  pipes,  but  connected  directly  to 
the  steam  space  in  the  boiler,  so  that  it  can  be  wrought  inde- 
pendently even  although  the  main  stop  valve  is  closed. 

The  branch  steam  pipe  between  the  stop  valves  and  the  engine 
must  be  arranged  to  suit  the  number  of  boilers;  where  two  boilers 
are  used,  the  main  pipe  branch  should  be  larger  than  the  branches 
from  the  boilers.     These  branch  pieces  are  fitted  with  expansion 


Fig.  343. — Stop  Valve. 

A,  Valve.    B,  Chest,    c,  Cover.    D,  Screwed  spindle. 
E,  Handle.      F,  Stuffing  box  and  gland. 


458 


MODERN   STEAM   PRACTICE. 


stuffing  boxes  and  glands,  to  suit  the  direction  of  the  expansion 
and  contraction  of  the  copper  pipes.  In  all  bends  care  must  be 
taken  to  fit  a  collar  on  the  end  of  the  pipe,  the  gland  and  bottom 


Fig.  344. — Branch  Steam  Pipe. 
A,  Branch  pipe.      B,  Stuffing  box  and  gland.      C,  Loose  bush. 

bush  being  first  placed  on  the  pipe ;  this  precaution  is  necessary, 
as  bends  under  pressure  have  a  tendency  to  assume  a  straight  line, 
and  fatal  accidents  have  occurred  from  the  steam  by  its  reactive 
force  blowing  out  the  bend  and  filling  the  engine  room  direct 
from  the  boiler. 

Clothing  the  steam  pipes.  —  In  order  to  prevent  condensation 
taking  place  in  the  passage  of  the  steam  to  the  cylinder,  all  the 
steam  pipes  should  be  carefully  clothed  with  felt,  secured  with  fine 
wire  wound  round  the  pipe,  and  covered  over  all  with  canvas  sewn 
tightly  on,  which  should  receive  two  or  three  coats  of  paint.  In 
some  instances  the  pipes  are  lagged  with  wood,  and  secured  with 
neat  brass  hoops. 

Separator. — Some  makers  fit  a  moisture  separator  to  the  steam 
pipes.  This  appliance  acts  by  abruptly  changing  the  flow  of 
the  steam,  and  is  similar  to  those  used  for  land  engines,  which 
have  been  explained  in  a  former  part  of  this  Work.  By  this  means 
much  of  the  moisture  is  got  rid  of,  trickling  down  the  baffle  plate 
to  the  bottom  of  the  separator,  and  then  run  off  by  a  valve  into  the 
bilges,  or  used  for  washing  and  cooking  purposes. 

Coveri7ig  the  boilers. — To  prevent  radiation,  and  consequently 
waste  of  fuel,  the  boilers  are  lagged  in  all  available  parts.  This 
form  of  lagging  consists  in  fastening  square  pieces  of  wood  at  the 
corners  and  at  intermediate  distances  on  the  boiler,  the  wood  being 
fastened  by  small  stud  bolts  and  nuts ;  felt  is  then  laid  in  between 


MARINE   ENGINES. 


459 


the  wooden  battens,  flush  with  the  top  of  the  wood,  and  the  lagging 
or  strips  of  wood,  which  are  grooved  and  feathered,  is  then  laid  on, 
and  securely  fastened  to  the  battens  with  screw  nails.  The  wood 
is  then  painted  all  over,  and  on  the  top  of  the  boiler  and  round  the 
top  corners  thin  sheet  lead  is  laid,  which  thoroughly  protects  the 
top  of  the  boiler  plates  from  the  moisture  that  lodges  on  the 
lagging,  and  would  run  between  the  joints  were  the  lead  not  form- 
ing an  effectual  waterproof  covering.  This  covering  also  keeps  the 
boiler  room  comparatively  cool.  In  many  examples,  however,  with 
dry  uptakes,  as  fitted  to  high-pressure  boilers,  lagging  cannot  be 
used,  because  it  would  ignite  and  smoulder  away;  in  these  cases 
the  boiler  room  is  kept  cool  by  air  spaces  formed  with  thin  plates 
placed  in  front  of  the  uptakes,  by  which  a  current  of  air  is  continu- 
ally flowing  up  between  the  uptakes  and  the  plates,  and  prevents 
in  a  great  measure  the  radiation  of  heat  afi"ecting  the  attendants. 

Check  valve.  —  The  valves  fitted  to  the  boiler  at  the  end  of  the 
feed  pipes,  termed  the  check  valves,  are  spindle  valves,  contained  in 


Fig.  345. — Check  Valve. 
A,  Valve.    B,  Chest,    c,  Cover,    d,  Set 


Fig.  246. — Check  Valve  and  Plug  Valve,  &c. 

A,  Plug  valve.     B,  Chest,     c,  Screwed  cover.     D,  Check 
valve.      E,  Handle. 


brass  valve  boxes ;  the  seating  is  turned  in  the  box,  and  the  valve 
ground  in,  having  a  separate  screwed  hand  spindle  passing  through 
a  stuffing  box  on  the  cover.  By  this  means,  when  no  water  is  re- 
quired in  the  boiler,  the  spindle  is  screwed  down  hard  on  the  top 
of  the  valve,  the  water  passing  through  the  pumps,  escaping  by 
the  relief  valve  into  the  hot  well.     This  valve  on  the  boiler  also 


460  MODERN   STEAM   PRACTICE. 

acts  as  a  non-return  valve,  easing  as  it  were  the  pipes  at  each  return 
stroke  of  the  pump,  and  in  the  event  of  any  of  the  feed  pipes  giving 
way  the  valve  of  course  instantly  shuts  with  the  steam  pressure, 
and  thus  prevents  an  escape  of  hot  water  and  steam  into  the  boiler 
room :  in  this  respect  it  may  be  termed  the  non-return  safety  valve. 
In  some  examples  a  plug  valve  has  been  fitted  in  connection  with 
the  non-return  valve  box.  This  is  a  refinement,  however,  which 
has  not  come  into  general  use;  ground  plug  valves  are  at  the  best 
very  imperfect,  and  give  a  great  deal  of  trouble  to  keep  them  in 
thorough  working  order.  It  will  be  seen  in  Fig.  346  that  there  is  a 
handle  secured  to  the  plug  at  the  bottom,  which  is  hollow ;  and  the 
non-return  valve  is  fitted  to  the  top  of  the  plug,  and  guided  by  a 
spindle  passing  upwards  through  a  hollow  tube  bored  in  the  cover.. 
TYiQ  gauge  glass  for  indicating  the  height  of  water  in  the  boiler  is 
fitted  to  brass  connecting  pieces  having  a  screwed  packing  gland,  with 
plug  tap  at  the  top,  and  two  taps  in  the  bottom  connection,  screwed 
into  a  separate  pipe,  on  which  bosses  are  cast  for  that  purpose; 
there  are  also  three  separate  test  taps  fitted  to  the  side  of  the  pipe; 
these  are  required,  as  the  gauge,  although  protected  with  a  shield, 
sometimes  breaks,  in  which  case  its  plug  taps  are  shut,  and  the 
attendant  ascertains  by  opening  the  side  taps  if  there  is  a  sufficient 
quantity  of  water  in  the  boiler.  These  taps  have  funnels  and  small 
pipes  for  blowing  the  water  down  into  the  bilge.  The  taps  on  the 
glass  gauge  should  be  so  arranged  on  the  branch  screwed  into  the 
large  pipe,  that  when  they  are  shut  a  nut  on  the  top  of  the  con- 
nection can  be  unscrewed,  and  a  new  glass  fitted  without  disturbing 
the  joints.  Plugs  have  sometimes  been  fitted  in  the  connection  in 
a  line  with  the  glass  gauge,  but  such  an  arrangement  is  not  quite 
convenient  when  a  tube  requires  refitting;  for,  in  the  former  plan 
the  nut  at  the  top  being  unscrewed  the  glass  tube  is  put  in  vertically, 
whereas  in  the  latter  the  nut  requires  to  be  edged  in,  and  conse- 
quently does  not  fit  so  nicely;  and  the  only  saving  effected  is  the 
small  test  tap  placed  at  the  bottom,  although  some  makers  fit  two 
taps  at  the  bottom,  one  over  the  other — an  arrangement  not  at  all 
required.  It  is  preferable  to  cast  the  pipe  which  carries  the  gauge 
glass  and  test  taps  in  brass,  or  a  copper  pipe  may  be  used,  with 
bosses  brazed  on  for  screwing  the  connection  to.  As  the  small 
taps  are  liable  to  get  choked  with  deposit,  they  should  be  always 
so  arranged  with  a  nut  on  the  connection  which  can  be  unscrewed, 
and  a  small  rod  pushed  through  to  clear  away  the  deposit.     ^ 


MARINE   ENGINES. 


461 


Scum  taps  are  fitted  in  connection  with  an  internal  pipe,  for 
collecting  the  froth  or  scum  at  about  the  level  of  the  water  in  the 
boiler,  and  a  copper  pipe  is  connected  to  the  tap  for  blowing  the 
dirty  water  overboard.  The  usual  blow-off  cock  is  fitted  to  the 
bottom  of  the  boiler,  with  pipe  connection  and  expansion  joints  on 
the  blow-off  Kingston  valves,  which  is  fitted  to  a  strong  cast-iron 
pipe  at  the  bottom  of  the  vessel. 

Vaaiuni  valve. — In  the  event  of  the  steam  in  the  boiler  falling 
below  the  atmospheric  pressure — or  a  partial  vacuum  being  formed — 
a  reverse  valve  is  fitted  to  the 
boiler.  It  is  of  the  spindle  kind, 
nicely  ground  into  its  seat  formed 
in  the  brass  valve  box.  The 
steam  acts  on  the  top  of  the  valve, 
while  the  bottom  is  open  to  the 


Vacuum  Valve. 

B,  Chest,      c,  Screw  cover. 
D,  Boiler. 


Fig.  348.— WhistlcL 

A,  Bell.     B,  Bottom  piece,     c  c,  Annular  space. 
D,  Plug  tap.      E,  Handle. 


atmosphere;  thus  when  a  partial  vacuum  is  formed  in  the  boiler 
the  atmospheric  pressure  lifts  the  valve,  and  the  vacuum  is  at  once 
destroyed,  consequently  the  flat  sides  of  the  boiler  have  no  tendency 
to  collapse. 

Steam  whistles  should  be  fitted  to  all  vessels,  for  use  in  foggy 
weather.  They  are  generally  placed  on  the  bridge,  with  a  pipe 
connection  to  the  boiler;  and  are  formed  exactly  like  the  steam 
whistle  for  the  locomotive  engine.  The  depth  of  the  bell  varies  to 
suit  the  note  desired ;  but  a  deep  bell,  producing  a  full  note  similar 
to  the  guard's  alarm  on  the  railway  engine,  is  desirable  for  ocean 
steam  ships. 


462 


MODERN   STEAM   PRACTICE. 


The  following  is  an  extract  from  a  Report  on  Safety  Valves, 
drawn  up  by  a  committee  of  the  Institution  of  Engineers  and  Ship- 
builders in  Scotland,^  which  presents  the  various  features  of  the 
question  of  area  and  method  of  loading  in  a  succinct  form: — 

"  Safety  Valve  Openings. — Since  an  orifice,  with  a  square- 
edged  entrance,  reduces  the  flow  from  12  to  14  per  cent.,  this  allow- 
ance will  require  to  be  made  in  computing  the  requisite  area,  and 
opening  of  a  safety  valve,  which  cannot  be  considered  as  presenting 
a  much  better  entrance  to  the  steam  than  a  square-edged  orifice. 
In  making  this  14  per  cent,  allowance  the  weight  in  pounds  of  steam 
discharged  per  minute  per  square  inch  of  opening,  with  square- 
edged  entrance,  corresponds  very  nearly  with  three-fourths  of  the 
absolute  pressure  in  the  boiler  as  long  as  that  pressure  is  not  less 
than  25-37  lbs.    Examples  of  this  are  shown  in  the  following  table: — 


Absolute  Pressure 

Weight  Discharged  per 

Square  Inch  of 
Orifice,  with  Rounded 
Entrance,  per  Minute. 

Weight  Discharged  per 

Three-fourths 

in  lbs.  per  Square 
Inch. 

Minute  with 
Square-edged  Orifice. 

of  Absolute  Pres- 
sure. 

Pv 

7CV. 

Ws. 

XA 

25-37 

22 -81 

19-6 

19 

30 

26-84 

23 

22-5 

40 

35-48 

30-5 

3°„ 

45 

39-78 

34-2 

33-8 

50 

44  06 

37-9 

37-5 

60 

52-59 

45-2 

45 

70 

61-07 

52-5 

52-5 

75 

65-30 

56-1 

56-2 

90 

77-94 

67 

67 -s 

100 

86-34 

74-3 

75 

The  area  of  opening,  requisite  to  the  discharge  of  any  given  con- 
stant weight  of  steam,  it  will  be^  observed,  is  very  nearly  in  the 
inverse  ratio  of  the  pressure.  Thus,  while  3  square  inches  of  open- 
ing, with  square-edged  entrance,  will  discharge  3x23  =  69  lbs, 
weight  of  30  lbs.  pressure  steam  per  minute,  one  square  inch  of 
opening  will  discharge  6^  lbs.  per  minute  of  90  lbs.  pressure  steam. 

The  quantity  of  heat,  however,  requisite  to  generate  (from  water 
at  100°)  6^  lbs.  weight  of  steam,  at  90  lbs.  pressure,  is  only  i  per 
cent,  less  than  is  required  to  evaporate  69  lbs.  at  30  lbs.  pressure. 

The  boiler  which  will  generate  69  lbs.  of  steam  per  minute  at 
30  lbs.  cannot,  therefore,  possibly  generate  more  than  677  lbs.  at  a 
pressure  of  90  lbs. ;  but  many  experiments  on  record  seem  to  indicate 
that  the  deficiency  at  the  higher  pressure  is  more  than  ten  per  cent. 

*  See  Trans,  of  that  Institution,  vol.  xviii. 


MARINE   ENGINES.  463 

In  ordinary  marine  practice  there  is  not  often  more  than  20  lbs. 
of  coal  consumed  per  hour  per  square  foot  of  fire  grate,  and  the 
water  evaporated  seldom  exceeds  9  lbs.  per  lb.  of  coal,  which  corre- 
sponds to  180  lbs.  per  hour,  or  an  evaporation  of  3  lbs.  per  minute 
per  square  foot  of  fire  grate.  Under  those  conditions  the  area  of 
opening  requisite  to  discharge  all  the  steam  a  boiler  can  generate 
corresponds  to  four  times  the  square  feet  of  fire  grate,  divided  by 
the  absolute  pressure;  or,  let  a  denote  the  area  of  orifice  in  square 
inches,  and/i  the  absolute  pressure — 

_4  X  square  feet  of  fire  grate 
a-  -  . 

The  Board  of  Trade  allowance  is  half  of  one  square  inch  area  of 
safety  valve  for  each  square  foot  of  fire  grate.  Hence,  the  lift  of 
valve  is  proportional  to  the  diameter,  and  inversely  as  the  pressure. 
For  a  discharge  of  3  lbs.  per  minute  per  square  foot  of  fire  grate  the 
requisite  lift  in  inches  is  twice  the  diameter  of  a  (flat-faced)  valve, 
divided  by  the  absolute  pressure;  this,  however,  does  not  apply  to 
pressures  less  than  25  lbs. 

Take,  for  example,  a  valve  5  inches  in  diameter,  19-6  square 
inches  in  area,  which  corresponds  to  2  x  I9'6  =  39'2  square  feet  of 
fire  grate,  which  would  evaporate  39'2X3  =  II7"6  lbs.  of  Avater  per 
minute.  Then  since  the  area  a  in  square  inches,  requisite  to  dis- 
charge any  weight,  w  in  lbs.  of  steam  per  minute  at  the  pressure 
/i  is— 

we  would   have,  by  taking  the   pressure  /  =  60,  and  the  weight 
w  =  II 7 '6,  the  area 

a  —  ^- '- —  =  2'6l  square  inches, 

3x  60 

which  corresponds  to  the  opening  of  a  flat-faced  valve,  5  inches 
diameter,  when  lifting  ^-~  =  •1667  inches. 

The  circumference  of  a  5-inch  valve  being  157  inches  and 
157  X  •1667  =  2'6i  square  inches  of  opening,  as  stated. 

When  the  angle  of  seat  of  valve  is  45°,  the  lift  required  in  inches 
i.s — 

2'8  X  diameter  of  valve 

When  a  boiler  is  regularly  fired,  and  all  the  steam  generated 
discharged  through  an  ordinary  safety  valve,  under  a  succession  of 


4^4  MODERN   STEAM   PRACTICE. 

dififerent  pressures,  the  lift  of  valve,  multiplied  by  those  absolute 
pressures,  should  be  a  constant  quantity,  provided  the  same  quantity 
of  heat  is  constantly  entering  the  boiler,  and  provided  also  that  the 
absolute  pressure  in  the  boiler  or  pipe  below  the  valve  is  not  less 
than  1726  times  the  absolute  pressure  of  the  steam  in  the  chamber 
above  the  valve. 

In  actual  experiment  a  deficiency  is  generally  manifested  at  the 
higher  pressures.  Hence  the  suspicion  of  some  considerable  loss  of 
heat  at  the  higher  temperatures. 

It  has  been  suggested  that  this  might  be  accounted  for  by  the 
low-pressure  steam  carrying  water  along  with  it — retarding  its 
motion — and  thereby  requiring  a  larger  opening;  but  this  would 
only  aggravate  the  case,  since  the  same  opening  will  permit  of  a 
much  larger  quantity  of  heat  being  discharged  from  the  boiler  with 
wet  than  with  dry  steam.  This  phenomenon  may  be  suggested  as 
one  worthy  of  further  investigation. 

According  to  the  Prussian  law,  as  taken  from  Engineering  of 
December  6th,  1872,  and  allowing  30  square  feet  of  heating  surface 
per.square  foot  of  fire  grate,  the  area  of  safety  valve  is — 

36  X  square  feet  of  fire  grate^ 

A  valve  of  this  size,  when  full  open,  is  capable  of  carrying  away 
nine  times  the  quantity  of  steam  generated  at  the  pressure /j,  and 
therefore  will,  at  the  designed  pressure  /j,  be  able  to  discharge  all 
the  steam  by  lifting  i-36th  part  of  its  diameter. 

At  absolute  pressures  of  72  lbs.,  the  British  and  Prussian  laws 
prescribe  precisely  the  same  area  of  valve. 

Take,  for  example,  20"36  square  feet  of  fire  grate,  which  requires 
by  British  rule  a  valve  lO'iS  square  inches  in  area,  equal  to  3 '6 
inches  diameter,  and  which  if  flat-faced  would,  at  a  pressure  of 

72  lbs.,  require  to  lift  ^  ^^     equal  to  i-ioth  of  an  inch. 

Then,  by  the  Prussian  rule  the  area  of  valve  is,  for  20'36  feet  of 

grate  and   72    lbs.  pressure:    a^^^   x  20  3  _  ^Q.^g  square  inches  = 

3-6  inches  diameter;  and  the  requisite  lift  is  (diameter  3-6)  as  before 

=  ^-7  =  i-ioth  of  an  inch.     The  circumference  of  this  valve  being 
36 

ir3i  inches,  would  (if  flat-faced)  by  lifting  i-ioth  inch  give  a  clear 
opening  of  I'i3i  square  inch,  which  opening  would,  at  72  lbs.  pres- 
sure, discharge  %^  X  72  X  i •131=61-07  lbs.  of  steam  per  minute,  and 
which  corresponds  to  3  lbs.  per  foot  of  fire  grate — as,  20*36  X  3  =61  '08. 


MARINE   ENGINES.  465 

At  absolute  pressures  of  36  lbs.  the  Prussian  law  prescribes  double, 
and  at  144  lbs.  only  half  the  area  of  the  British. 

At  all  pressures  above  1726  atmosphere,  the  area  of  valve  when 
full  open,  by  Prussian  rule,  is  nine  times  that  requisite  to  discharge 
all  the  steam  generated,  while  by  British  rule  it  is  4^  times  at  36  lbs. 
pressure,  and  18  times  more  than  is  required  at  144  lbs.  absolute 
pressure;  and  this  is  after  allowing  for  an  evaporation  of  3  lbs.  of 
water  per  minute  per  square  foot  of  fire  grate,  which  is  considerably 
more  than  is  usually  realized  in  marine  practice. 

Before  the  ordinary  valves  rise  and  give  sufficient  opening,  the 
pressure  of  steam  frequently  greatly  exceeds  the  load  under  which 
the  valve  begins  to  rise.  Hence  the  requirement  of  large  areas. 
With  a  properly  constructed  valve,  however,  such  as  many  now  in 
use,  which  rise  one-fourth  of  their  diameter  by  an  increment  of  i  to 
3  lbs.  above  the  load,  there  is  no  necessity  for  the  area  being  much 
(if  any)  more  than   i-Qth  of  that  prescribed  by  the  Prussian  rule. 

S4  X  square  ft.  of  grate      1,1  r      •  r        i  t^-l 

ay,  area  a^i- — ^ —  plus  the  area  01  wmgs  01  valve.      Ihe 

valves  here  referred  to  are  so  very  small  that  the  stems,  or  wings, 
occupy  a  considerable  proportion  of  the  area,  and  must  in  the  above 
equation  be  allowed  for.  Those  small  valves  give  much  more 
prompt  relief  to  the  boiler,  and  never  permit  the  pressure  to  rise 
much  beyond  the  load. 

"Result  of  a  Series  of  Experiments,  made  to  ascertain 
the  increase  of  pressure  in  a  boiler  when  all  the  steam  raised  was 
allowed  to  pass  away  by  the  safety  valves  unassisted. — Two  valves 
were  used,  the  united  area  of  which  was  half  an  inch  per  foot  of 
grate  surface.  The  boiler  used  was  tubular,  with  2  furnaces;  the 
grate  surface  was  25  square  feet;  the  heating  surface  746  square 
feet.  The  valves  were  each  2^  inches  diameter,  the  fuel  used  was 
ordinary  good  Glasgow  dross,  the  firing  good,  and  as  nearly  uniform 
during  all  the  experiments  as  possible.  The  valves  were  loaded  by 
direct  weights.     On  next  page  we  give  table  of  results. 

With  flat-faced  valves  having,  according  to  Board  of  Trade  rule, 

•?  P  L 
half  of  one  square  inch  area  per  foot  of  fire  grate,  W  =  ^^-^  • 

But  the  valve  seats  being  to  an  angle  of  45  degrees, 

3  P  L 
W  =  -:g-g  =  Weight  of  steam  discharged  per  minute  per  square  foot  of  fire  grate. 

P  =  Absolute  pressure  in  lbs.  per  square  inch. 
D  =  Diameter  of  valve  in  inches. 
L=Lift  of  valve  in  inches. 

SO 


466 


MODERN   STEAM   PRACTICE. 


Load  on  Valve. 

Press,  rose  to 

Incr.  per  cent. 

Lift  of  Valve. 

W.  Lbs.      • 

5  lbs. 

13   lbs. 

i6o- 

•325 

3 '39 

lO    „ 

19      ,, 

90- 

•255 

3-223 

15  ,. 

25      „ 

66- 

•18 

2-68 

20  ,, 

30      „ 

50- 

•16 

2-676 

25  „ 

36      „ 

44' 

•1425 

27 

30  „ 

40      „ 

33" 

•1262 

2-58 

35   „ 

44     ,, 

257 

•II25 

2 '466 

40   „ 

4&/2„ 

21- 

•103 

2-4:j 

45    „ 

52     „ 

15-5 

•097 

2-41 

The  guides  of  valve  would  reduce  the  clear  opening  by  full  one- 
ninth,  for  which  no  allowance  has  in  the  above  been  made. 

Table  showing  the  respective  area  of  valve  for  the  boiler  in 
question,  if  made  according  to  the  committee's  recommendation,  as 
compared  with  present  practice  in  this  country,  and  at  the  several 
undernoted  absolute  pressures: — 


Absolute 
Pressure 
of  Steam. 

Areas  of  Valve  as 

recommended  by 

Committee. 

Areas  of  British 
Valves. 

20  lbs. 

45  •      square  in. 

12-5  square  in. 

25     „ 

36- 

12-5 

30    „ 

30- 

12-5 

35     „ 

257 

12-5 

40    „ 

22-5 

12-5 

45    „ 

20-                 ,, 

12-5 

50    „ 

iS- 

125 

55    „ 

16-36           „ 

12-5 

60   „ 

15' 

12-5 

65    „ 

13-84        „ 

12-5 

70   „• 

13- 

12-5        „ 

75    >, 

12'                 „ 

12-5 

Safety  valves  of  ordinary  construction,  if  loaded  by  direct  weight, 
do  not  allow  all  the  steam  to  escape  which  can  be  raised  in  the 
boiler  until  the  pressure  has  increased  above  that  at  which  the 
valve  opens,  and  an  additional  increase  of  pressure  will  take  place 
Avhen  the  valves  are  loaded  by  springs.  That  such  has  been  the 
case  in  the  past  by  dead-weight  loading  and  imperfectly  propor- 
tioned valves  is  fully  illustrated  by  reference  to  the  foregoing 
experiments. 

The  object  in  appointing  this  committee  was  to  investigate  the 
cause  of  this  increase  of  pressure,  especially  with  boilers  propor- 
tioned in  strength  to  work  at  low  pressures,  and  it  is  hoped  that  the 
result  of  these  investigations  will  clearly  show  that  the  great  cause 


MARINE   ENGINES.  467 

lay  in  using  valves  of  too  small  dimensions;  and  that  with  valves 
proportioned  as  proposed,  properly  constructed  and  loaded  by 
springs,  anything  approaching  a  dangerous  increase  of  pressure  is 
entirely  avoided. 

"  On  Loading  Safety  Valves  by  Direct  Springs.  —  It 
has   been   shown   that   valves   having   half  an    inch   of  area   per 

fo.       r            .               c                      -A.       iTi.    2  X  diameter  of  valve     • 
ot  of  grate   surface   require   to   liit  p m 

order  perfectly  to  relieve  the  boiler;  and  if  proportioned  as  is 
recommended  in  this  report,  then  the  lift  would  be  in  all  cases 

diameter  of  valve. 

36  ^ 

Having  determined  the  requisite  lift,  it  remains  to  fix  any  reason- 
able or  desired  per  centage  of  the  load,  which  is  not  to  be  exceeded 
by  the  additional  load  due  to  the  compression  or  extension  of  the 
spring,  caused  by  the  lift  of  the  valve.  Let  this,  for  example,  be 
restricted  to  2^  per  cent,  of  the  original  load. 

Then  the  spring  loading  the  valve  should  be  so  proportioned  that 
the  compression  or  extension,  to  produce  the  initial  load,  shall  be 
40  times  the  lift  of  the  valve. 

So  that  with  valves  having  half  an  inch  area  per  foot  of  grate 
surface,  the  initial  compression  or  extension  of  spring  would  be  = 

80  X  diameter  of  valve        -.-xt  11  1     1    .1        •    •,•    1 

p .  With  valves  as  recommended,  the  initial  com- 
pression or  extension  would  be  rii  X  diameter  of  valve.  The 
following  formula  refers  to  spiral  springs,  made  of  steel  in  the  usual 
way: — 

E=  Compression  or  extension  of  one  coil  in  inches. 

d=  Diameter  from  centre  to  centre  of  steel  composing  spring  in 

inches. 
w  =  Weight  applied  in  pounds. 
D  =  Diameter  or  side  of  square  of  steel  of  which  the  spring  is 

made  in  i6ths  of  an  inch. 
C  =  A  constant  which,  from  experiments  made,  may  be  taken 

as  22  for  round  steel  and  30  for  square  steel. 


E  = 


D*xC* 


The  total  compression  or  extension  of  such  a  spring  is  equal  to 
that  of  one  coil  into  the  number  of  effective  coils,  which  may 
be  taken   as  two  less  than   the  apparent   number,  the  end  coils 


468  MODERN   STEAM    PRACTICE. 

being  usually  flattened   to  serve  as  bases  for  the  spring  to  rest 
upon. 

The  relation  between  the  safe  load,  size  of  steel,  and  the  diameter 
of  the  coil  has  been  deduced  from  the  works  of  the  late  Professor 
Rankine,  and  may  be  taken  for  practical  purposes  as  follows: — 

D  =   a/  for  round  steel. 

^  =  A  /  — ; for  square  steel. 

The  application  of  the  above  formulse  may  be  illustrated  by  the 
following  calculations  of  three  different  proportions  of  springs,  all 
designed  to  give  the  same  result.  Diameter  of  valve,  4"=  125  area 
in  square  inches.  Boiler  pressure  60  lbs.  per  square  inch.  Omitting 
weight  of  valve,  spindle,  and  spring;  load  required  =:I2'5  x  60  =  750 
lbs.  Then,  assuming  that  this  valve  is  in  the  proportion  of  half  a 
square  inch  area  per  foot  of  grate  surface,  the  lift  of  valve  would 

be=?-^="io5,  say  'i". 

75  -^ 

Initial  compression  of  spring,  S^iA  =  4"-26,  say  4  inches. 

1st.  Supposed  diameter  of  spring,  or  d,  equal  4  in.    D  =  a/ ^^°  ^  ^ 
=  10,  diameter  of  spring-  steel  =  io-i6ths.     E  =  -^^^'^°-  =  -218". 

'  ^         ^  lOOOO  X  22 

Effective  number  of  coils  =  7^  =  i8'3,  say  18.      Pitch  of  spiral, 

allowing  between  each  coil  a  distance  equal  to  twice  the  intended 
compression  =  i"*o6i,  say  i  inch;  effective  length  of  spring 
=  18  X  1  =  18",  and  allowing  for  two  end  coils  as  bases,  say  193^",  = 
the  length  of  spring  before  compression. 

2d.  Supposed  diameter  of  spring,  6  in.  D=  \/  J^  =  1 1  "447, 
sav   i2-i6ths.      E  =  ^'^^  ^^°  =  '355".      Effective  number  of  coils 

■^  20736  X  22  ^-'-' 

required,  y^  =  ir2,  say  i  r.     Pitch  of  spiral,  i*46";  effective  length 

of  spring,   i'46  x  11  =  i6'o6",  and  allowing  for  two  end  abutment 
coils,  say  17^2"  =  the  length  of  spring  before  compression. 

3d.  Supposed  diameter  of  spring  12  in.    D  =   V  "^^ —  ~  I4*42, 

say  i4-i6ths.     E  =  Tfj^^^  =  i"533"-      Effective  number  of  coils 

required,  -4^  =  2-6i.    Pitch  of  spiral,  3-9";  effective  length  of  spring. 


MARINE   ENGINES.  469 

3*9  X  2-6i  =  IOT7",  say  10",  and  allowing  for  two  end  abutment  coils, 
say  1 1  ^"  =  the  length  of  spring  before  compression. 

In  cases  where  it  is  desirable  or  perhaps  necessary  to  employ 
springs  acting  at  the  ends  of  levers,  the  same  formulas  can  Le  em- 
ployed for  determining  the  proportion  of  springs,  bearing  in  mind 
that  the  lift  of  the  end  of  the  lever  where  the  spring  is  attached,  is 
to  be  taken  instead  of  the  simple  lift  of  valve. 

The  above  illustrative  calculations  have  all  reference  to  springs 
made  of  round  steel,  and  used  in  compression.  In  many  cases  two 
or  more  springs,  one  within  the  other,  may  be  used  with  advantage. 

After  consideration  of  the  whole  of  the  experimental  information 
obtained,  and  the  necessities  required  in  practice,  the  committee 
have  come  to  the  following  conclusions: — 

1st.  The  present  practice  in  this  country  of  constructing  safety 
valves  of  uniform  size  for  all  pressures  is  incorrect. 

2d.  The  valves  should  be  flat-faced,  and  the  breadth  of  face  need 
not  exceed  one-twelfth  of  an  inch. 

3d.  The  present  system  of  loading  valves  on  marine  boilers  by 
direct  weight  is  faulty,  and  ill  adapted  for  sea-going  vessels,  a  con- 
siderable quantity  of  steam  being  lost  during  heavy  weather,  in 
consequence  of  the  reduced  effect  of  direct  load — the  result  of  the 
angle  or  list  of  the  vessel,  and  also  of  the  inertia  of  the  weight 
itself,  the  latter  not  being  self-accommodating  at  once  to  the  down- 
ward movements  of  the  vessel,  and,  moreover,  the  impossibility  of 
keeping  the  valves  when  so  loaded  in  good  working  order. 

4th,  That  two  safety  valves  be  fitted  to  each  marine  boiler,  one 
of  which  should  be  an  easing  valve. 

5th,  The  dimensions  of  each  of  these  valves,  if  of  the  ordinary 
construction,  should  be  calculated  by  the  following  rule: — 

.       18  xG       .       o-6xHS 
A=-^-orA  =  ^, 

A  =  Area  of  valve  in  square  inches. 
G  =  Grate  surface  in  square  feet. 
H  S  =  Heating  surface  in  square  feet. 

P  =  Absolute  pressure  in  lbs.  per  square  inch. 

6th.  The  committee  suggest  that  only  one  of  the  valves  may  be 
of  the  ordinary  kind,  and  proportioned  as  above,  and  that  it  should 
be  the  easing  valve.  The  other  may  be  so  constructed  as  to  lift 
one  quarter  of  its  diameter  without  increase  of  pressure.  Valves 
of  this  kind  are  now  in  use,  and  one  such  valve,  if  calculated  by 


470 


MODERN    STEAM    PRACTICE. 


the   following   rule,   would   be   of  itself  sufficient   to   relieve    the 
boilers : — 

A  =  ■ — p \-  area  of  guides  of  valve. 

Or  A  =     •^■^  ^ +  area  of  guides  of  valves. 


This  valve  should  be  loaded,  say  l  lb.  per  square  inch,  less  than 

the  easing  valve. 

7th.  As  experience  in 
the  use  of  valves  of  this 
description  is  acquired, 
both  may  be  of  this  kind, 
and  one  of  them  made  to 
blow  into  the  sea  without 
any  increase  of  pressure, 
as  is  illustrated  by  the  dia- 
grams (Figs.  348A— 348c) 
from  actual  practice;  the 
other  to  be  the  easing 
valve,  and  loaded  i  lb.  per 
square  inch  in  excess  of 
the  working  valve. 

8th.  If  the  heating  sur- 
face exceeds   30  feet   per 
foot   of  grate   surface,    the   size   of  safety 
valve  is  to  be  determined  by  the  heating 
surface. 

9th.  As  boilers  decay  from  age  it  is 
necessary  gradually  to  reduce  the  pressure 
of  steam,  and  the  committee  recommend 
that  valves  should  be  made  of  a  size  to  suit 
the  pressure  to  which  the  boiler  may  ulti- 
mately be  worked  when  it  becomes  old. 

loth.    Springs    should    be    adopted    for 
loading  safety  valves,  and  they  should  be 
direct-acting  where  practicable. 

When  levers  are  used,  the  friction  of  the  joints  will  cause  an 
extra  resistance,  and  consequent  increase  of  pressure,  when  the 
valve  is  rising,  and  a  loss  of  steam  through  diminution  of  pressure 
before  it  will  close." 


Figs.  348A,  348B. — A,  Safety  valve.  B,  Spring.  CC,  Studs 
with  screwed  ends.  D,  Cap.  E  E,  Chest  leading  to  v/aste 
pipe  and  nozzle  at  the  side  of  ship.  F,  Hand  lever  for  lift- 
ing valve. 


Fig.  348c — Section  of  Silent  Blow- 
off  Nozzle  on  Ship's  side.  A, 
Pipe  from  safety  valve.  B, 
Nozzle,  c.  Nozzle  chest.  D, 
Ship's  side. 


/ 


306 


bf) 


ACME 

SEP  28    1993 

100  CAMBRIDGE  STREET 
CHARLESTOWN,  MASS 


